Use updated _get_requisition API

91 files changed, 241 insertions, 133 deletions

diff --git a/contrib/ufo-med-mad-reject-2d-task.c b/contrib/ufo-med-mad-reject-2d-task.c
index b893fdc..7766309 100644
--- a/contrib/ufo-med-mad-reject-2d-task.c
+++ b/contrib/ufo-med-mad-reject-2d-task.c
@@ -95,9 +95,9 @@ ufo_med_mad_reject_2d_task_setup (UfoTask *task,
 static void
 ufo_med_mad_reject_2d_task_get_requisition (UfoTask *task,
                                             UfoBuffer **inputs,
-                                            UfoRequisition *requisition)
+                                            UfoRequisition *requisition,
+                                            GError **error)
 {
-  //  requisition->n_dims = 0;
   // Transferring the buffer «size» (size, data type and dimension) to the output
   ufo_buffer_get_requisition(inputs[0], requisition);
 }
diff --git a/contrib/ufo-med-mad-reject-task.c b/contrib/ufo-med-mad-reject-task.c
index 2c19c38..7c634d9 100644
--- a/contrib/ufo-med-mad-reject-task.c
+++ b/contrib/ufo-med-mad-reject-task.c
@@ -95,9 +95,9 @@ ufo_med_mad_reject_task_setup (UfoTask *task,
 static void
 ufo_med_mad_reject_task_get_requisition (UfoTask *task,
                                          UfoBuffer **inputs,
-                                         UfoRequisition *requisition)
+                                         UfoRequisition *requisition,
+                                         GError **error)
 {
-  //    requisition->n_dims = 0;
   // Transferring the buffer «size» (size, data type and dimension) to the output
   ufo_buffer_get_requisition(inputs[0], requisition);
 }
diff --git a/contrib/ufo-ocl-1liner-task.c b/contrib/ufo-ocl-1liner-task.c
index aa28a4c..e941fdd 100644
--- a/contrib/ufo-ocl-1liner-task.c
+++ b/contrib/ufo-ocl-1liner-task.c
@@ -131,7 +131,8 @@ ufo_ocl_1liner_task_setup (UfoTask *task,
 static void
 ufo_ocl_1liner_task_get_requisition (UfoTask *task,
                                      UfoBuffer **inputs,
-                                     UfoRequisition *requisition)
+                                     UfoRequisition *requisition,
+                                     GError **error)
 {
   // In the current version of the kernel all the inputs are supposed to have the same dimensions
   // Or more precisely the output has the same dimension as first input (indexed 0) and one work-item
diff --git a/contrib/ufo-stat-monitor-task.c b/contrib/ufo-stat-monitor-task.c
index 5c04fe9..2a11d6d 100644
--- a/contrib/ufo-stat-monitor-task.c
+++ b/contrib/ufo-stat-monitor-task.c
@@ -197,7 +197,8 @@ ufo_stat_monitor_task_setup (UfoTask *task,
 static void
 ufo_stat_monitor_task_get_requisition (UfoTask *task,
                                        UfoBuffer **inputs,
-                                       UfoRequisition *requisition)
+                                       UfoRequisition *requisition,
+                                       GError **error)
 {
     /* In the current version the statistics are NEVER the output of the filter.
      * Indeed is behaving as a /pass-through/ filter, doing nothing to the
diff --git a/src/ufo-average-task.c b/src/ufo-average-task.c
index 6566019..6e77ccb 100644
--- a/src/ufo-average-task.c
+++ b/src/ufo-average-task.c
@@ -62,8 +62,9 @@ ufo_average_task_setup (UfoTask *task,
 
 static void
 ufo_average_task_get_requisition (UfoTask *task,
-                                   UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                  UfoBuffer **inputs,
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     UfoAverageTaskPrivate *priv;
 
diff --git a/src/ufo-backproject-task.c b/src/ufo-backproject-task.c
index 35d3c4e..c123aeb 100644
--- a/src/ufo-backproject-task.c
+++ b/src/ufo-backproject-task.c
@@ -211,7 +211,8 @@ release_lut_mems (UfoBackprojectTaskPrivate *priv)
 static void
 ufo_backproject_task_get_requisition (UfoTask *task,
                                       UfoBuffer **inputs,
-                                      UfoRequisition *requisition)
+                                      UfoRequisition *requisition,
+                                      GError **error)
 {
     UfoBackprojectTaskPrivate *priv;
     UfoRequisition in_req;
@@ -227,8 +228,11 @@ ufo_backproject_task_get_requisition (UfoTask *task,
     priv->burst_projections = (guint) in_req.dims[1];
 
     if (priv->burst_projections > priv->n_projections) {
-        g_error("Total number of projections (%u) must be greater than "
-                "or equal to sinogram height (%u)", priv->n_projections, priv->burst_projections);
+        g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                     "Total number of projections (%u) must be greater than "
+                     "or equal to sinogram height (%u)",
+                     priv->n_projections, priv->burst_projections);
+        return;
     }
 
     requisition->n_dims = 2;
diff --git a/src/ufo-bin-task.c b/src/ufo-bin-task.c
index 9713b51..866a6b8 100644
--- a/src/ufo-bin-task.c
+++ b/src/ufo-bin-task.c
@@ -77,7 +77,8 @@ ufo_bin_task_setup (UfoTask *task,
 static void
 ufo_bin_task_get_requisition (UfoTask *task,
                               UfoBuffer **inputs,
-                              UfoRequisition *requisition)
+                              UfoRequisition *requisition,
+                              GError **error)
 {
     UfoBinTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-binarize-task.c b/src/ufo-binarize-task.c
index 913300c..ce9467b 100644
--- a/src/ufo-binarize-task.c
+++ b/src/ufo-binarize-task.c
@@ -70,7 +70,8 @@ ufo_binarize_task_setup (UfoTask *task,
 static void
 ufo_binarize_task_get_requisition (UfoTask *task,
                                    UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                   UfoRequisition *requisition,
+                                   GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-blur-task.c b/src/ufo-blur-task.c
index e3a0220..16b4b41 100644
--- a/src/ufo-blur-task.c
+++ b/src/ufo-blur-task.c
@@ -87,8 +87,9 @@ ufo_blur_task_setup (UfoTask *task,
 
 static void
 ufo_blur_task_get_requisition (UfoTask *task,
-                                        UfoBuffer **inputs,
-                                        UfoRequisition *requisition)
+                               UfoBuffer **inputs,
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     UfoBlurTaskPrivate *priv;
 
diff --git a/src/ufo-buffer-task.c b/src/ufo-buffer-task.c
index 89825ad..199098d 100644
--- a/src/ufo-buffer-task.c
+++ b/src/ufo-buffer-task.c
@@ -94,7 +94,8 @@ ufo_buffer_task_setup (UfoTask *task,
 static void
 ufo_buffer_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     UfoBufferTaskPrivate *priv;
 
diff --git a/src/ufo-calculate-task.c b/src/ufo-calculate-task.c
index c617314..0c5cac5 100644
--- a/src/ufo-calculate-task.c
+++ b/src/ufo-calculate-task.c
@@ -108,7 +108,8 @@ ufo_calculate_task_setup (UfoTask *task,
 static void
 ufo_calculate_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-center-of-rotation-task.c b/src/ufo-center-of-rotation-task.c
index aa200fa..c66e234 100644
--- a/src/ufo-center-of-rotation-task.c
+++ b/src/ufo-center-of-rotation-task.c
@@ -64,7 +64,8 @@ ufo_center_of_rotation_task_setup (UfoTask *task,
 static void
 ufo_center_of_rotation_task_get_requisition (UfoTask *task,
                                              UfoBuffer **inputs,
-                                             UfoRequisition *requisition)
+                                             UfoRequisition *requisition,
+                                             GError **error)
 {
     requisition->n_dims = 0;
 }
diff --git a/src/ufo-clip-task.c b/src/ufo-clip-task.c
index 78eb5a9..243d00e 100644
--- a/src/ufo-clip-task.c
+++ b/src/ufo-clip-task.c
@@ -80,7 +80,8 @@ ufo_clip_task_setup (UfoTask *task,
 static void
 ufo_clip_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-concatenate-result-task.c b/src/ufo-concatenate-result-task.c
index 5fc01c8..5a80272 100644
--- a/src/ufo-concatenate-result-task.c
+++ b/src/ufo-concatenate-result-task.c
@@ -77,8 +77,9 @@ ufo_concatenate_result_task_setup (UfoTask *task,
 
 static void
 ufo_concatenate_result_task_get_requisition (UfoTask *task,
-                                 UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                             UfoBuffer **inputs,
+                                             UfoRequisition *requisition,
+                                             GError **error)
 {
     requisition->n_dims = 1;
     /* Output size varies according to number of inputs to merge, and data
diff --git a/src/ufo-contrast-task.c b/src/ufo-contrast-task.c
index 4f68f75..6712845 100644
--- a/src/ufo-contrast-task.c
+++ b/src/ufo-contrast-task.c
@@ -72,7 +72,8 @@ ufo_contrast_task_setup (UfoTask *task,
 static void
 ufo_contrast_task_get_requisition (UfoTask *task,
                                    UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                   UfoRequisition *requisition,
+                                   GError **error)
 {
     ufo_buffer_get_requisition(inputs[0], requisition);
 }
diff --git a/src/ufo-correlate-stacks-task.c b/src/ufo-correlate-stacks-task.c
index ff4be50..de98c74 100644
--- a/src/ufo-correlate-stacks-task.c
+++ b/src/ufo-correlate-stacks-task.c
@@ -101,7 +101,8 @@ ufo_correlate_stacks_task_setup (UfoTask *task,
 static void
 ufo_correlate_stacks_task_get_requisition (UfoTask *task,
                                            UfoBuffer **inputs,
-                                           UfoRequisition *requisition)
+                                           UfoRequisition *requisition,
+                                           GError **error)
 {
     UfoCorrelateStacksTaskPrivate *priv;
     UfoRequisition ref_req;
diff --git a/src/ufo-crop-task.c b/src/ufo-crop-task.c
index cb53662..80d3a18 100644
--- a/src/ufo-crop-task.c
+++ b/src/ufo-crop-task.c
@@ -72,7 +72,8 @@ ufo_crop_task_setup (UfoTask *task,
 static void
 ufo_crop_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     UfoCropTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-cut-sinogram-task.c b/src/ufo-cut-sinogram-task.c
index 2e586af..4eb02c9 100644
--- a/src/ufo-cut-sinogram-task.c
+++ b/src/ufo-cut-sinogram-task.c
@@ -68,8 +68,9 @@ ufo_cut_sinogram_task_setup (UfoTask *task,
 
 static void
 ufo_cut_sinogram_task_get_requisition (UfoTask *task,
-                                      UfoBuffer **inputs,
-                                      UfoRequisition *requisition)
+                                       UfoBuffer **inputs,
+                                       UfoRequisition *requisition,
+                                       GError **error)
 {
     UfoCutSinogramTaskPrivate *priv = UFO_CUT_SINOGRAM_TASK_GET_PRIVATE (task);
 
diff --git a/src/ufo-cut-task.c b/src/ufo-cut-task.c
index 5ba43d7..fcf5d9d 100644
--- a/src/ufo-cut-task.c
+++ b/src/ufo-cut-task.c
@@ -70,7 +70,8 @@ ufo_cut_task_setup (UfoTask *task,
 static void
 ufo_cut_task_get_requisition (UfoTask *task,
                               UfoBuffer **inputs,
-                              UfoRequisition *requisition)
+                              UfoRequisition *requisition,
+                              GError **error)
 {
     UfoCutTaskPrivate *priv;
     UfoRequisition in_req;
@@ -80,8 +81,9 @@ ufo_cut_task_get_requisition (UfoTask *task,
     ufo_buffer_get_requisition (inputs[0], &in_req);
 
     if (priv->width >= in_req.dims[0]) {
-        g_warning ("Width %u larger than input width %zu", priv->width, in_req.dims[0]);
-        width = 2;
+        g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                     "Cut width %u larger than input width %zu", priv->width, in_req.dims[0]);
+        return;
     }
     else {
         width = in_req.dims[0] - priv->width;
diff --git a/src/ufo-cv-show-task.cpp b/src/ufo-cv-show-task.cpp
index d60a50b..c901766 100644
--- a/src/ufo-cv-show-task.cpp
+++ b/src/ufo-cv-show-task.cpp
@@ -67,7 +67,8 @@ ufo_cv_show_task_setup (UfoTask *task,
 static void
 ufo_cv_show_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-denoise-task.c b/src/ufo-denoise-task.c
index 4d8293c..c3da254 100644
--- a/src/ufo-denoise-task.c
+++ b/src/ufo-denoise-task.c
@@ -91,7 +91,8 @@ ufo_denoise_task_setup (UfoTask *task,
 static void
 ufo_denoise_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-detect-edge-task.c b/src/ufo-detect-edge-task.c
index 4009d31..a0a4f9e 100644
--- a/src/ufo-detect-edge-task.c
+++ b/src/ufo-detect-edge-task.c
@@ -103,7 +103,8 @@ ufo_detect_edge_task_setup (UfoTask *task,
 static void
 ufo_detect_edge_task_get_requisition (UfoTask *task,
                                       UfoBuffer **inputs,
-                                      UfoRequisition *requisition)
+                                      UfoRequisition *requisition,
+                                      GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-dfi-sinc-task.c b/src/ufo-dfi-sinc-task.c
index d01bba0..3245a9c 100644
--- a/src/ufo-dfi-sinc-task.c
+++ b/src/ufo-dfi-sinc-task.c
@@ -169,9 +169,9 @@ ufo_dfi_sinc_task_setup (UfoTask *task,
 static void
 ufo_dfi_sinc_task_get_requisition (UfoTask *task,
                                    UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                   UfoRequisition *requisition,
+                                   GError **error)
 {
-    //set output requsition
     UfoRequisition input_requisition;
     ufo_buffer_get_requisition (inputs[0], &input_requisition);
 
diff --git a/src/ufo-dummy-data-task.c b/src/ufo-dummy-data-task.c
index e6c6aa3..af6dd61 100644
--- a/src/ufo-dummy-data-task.c
+++ b/src/ufo-dummy-data-task.c
@@ -77,8 +77,9 @@ ufo_dummy_data_task_setup (UfoTask *task,
 
 static void
 ufo_dummy_data_task_get_requisition (UfoTask *task,
-                                   UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                     UfoBuffer **inputs,
+                                     UfoRequisition *requisition,
+                                     GError **error)
 {
     UfoDummyDataTaskPrivate *priv;
 
diff --git a/src/ufo-dump-ring-task.c b/src/ufo-dump-ring-task.c
index 36b81da..27491ab 100644
--- a/src/ufo-dump-ring-task.c
+++ b/src/ufo-dump-ring-task.c
@@ -61,7 +61,8 @@ ufo_dump_ring_task_setup (UfoTask *task,
 static void
 ufo_dump_ring_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     ufo_buffer_get_requisition(inputs[0], requisition);
 }
diff --git a/src/ufo-duplicate-task.c b/src/ufo-duplicate-task.c
index 3541a90..5491362 100644
--- a/src/ufo-duplicate-task.c
+++ b/src/ufo-duplicate-task.c
@@ -53,7 +53,8 @@ ufo_duplicate_task_setup (UfoTask *task,
 static void
 ufo_duplicate_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     ufo_buffer_get_requisition(inputs[0], requisition);
 }
diff --git a/src/ufo-fft-task.c b/src/ufo-fft-task.c
index 73154f7..a953791 100644
--- a/src/ufo-fft-task.c
+++ b/src/ufo-fft-task.c
@@ -101,7 +101,8 @@ ufo_fft_task_setup (UfoTask *task,
 static void
 ufo_fft_task_get_requisition (UfoTask *task,
                               UfoBuffer **inputs,
-                              UfoRequisition *requisition)
+                              UfoRequisition *requisition,
+                              GError **error)
 {
     UfoFftTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-fftmult-task.c b/src/ufo-fftmult-task.c
index 09db154..6e722c1 100644
--- a/src/ufo-fftmult-task.c
+++ b/src/ufo-fftmult-task.c
@@ -67,7 +67,8 @@ ufo_fftmult_task_setup (UfoTask *task,
 static void
 ufo_fftmult_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition(inputs[1], requisition);
 }
diff --git a/src/ufo-filter-particle-task.c b/src/ufo-filter-particle-task.c
index 0964b41..46d5ae5 100644
--- a/src/ufo-filter-particle-task.c
+++ b/src/ufo-filter-particle-task.c
@@ -70,7 +70,8 @@ ufo_filter_particle_task_setup (UfoTask *task,
 static void
 ufo_filter_particle_task_get_requisition (UfoTask *task,
                                           UfoBuffer **inputs,
-                                          UfoRequisition *requisition)
+                                          UfoRequisition *requisition,
+                                          GError **error)
 {
     UfoFilterParticleTaskPrivate *priv = UFO_FILTER_PARTICLE_TASK_GET_PRIVATE (task);
     requisition->n_dims = 1;
diff --git a/src/ufo-filter-stripes-task.c b/src/ufo-filter-stripes-task.c
index 48c707c..6a0eedd 100644
--- a/src/ufo-filter-stripes-task.c
+++ b/src/ufo-filter-stripes-task.c
@@ -95,8 +95,9 @@ ufo_filter_stripes_task_setup (UfoTask *task,
 
 static void
 ufo_filter_stripes_task_get_requisition (UfoTask *task,
-                                 UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                         UfoBuffer **inputs,
+                                         UfoRequisition *requisition,
+                                         GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-filter-stripes1d-task.c b/src/ufo-filter-stripes1d-task.c
index fa36707..816f3aa 100644
--- a/src/ufo-filter-stripes1d-task.c
+++ b/src/ufo-filter-stripes1d-task.c
@@ -125,7 +125,8 @@ ufo_filter_stripes1d_task_setup (UfoTask *task,
 static void
 ufo_filter_stripes1d_task_get_requisition (UfoTask *task,
                                            UfoBuffer **inputs,
-                                           UfoRequisition *requisition)
+                                           UfoRequisition *requisition,
+                                           GError **error)
 {
     UfoFilterStripes1dTaskPrivate *priv;
 
diff --git a/src/ufo-filter-task.c b/src/ufo-filter-task.c
index 73697fe..64016eb 100644
--- a/src/ufo-filter-task.c
+++ b/src/ufo-filter-task.c
@@ -277,7 +277,8 @@ compute_faris_byer_coefficients (UfoFilterTaskPrivate *priv,
 static void
 ufo_filter_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     UfoFilterTaskPrivate *priv;
 
diff --git a/src/ufo-flat-field-correct-task.c b/src/ufo-flat-field-correct-task.c
index 8fb615b..fe39439 100644
--- a/src/ufo-flat-field-correct-task.c
+++ b/src/ufo-flat-field-correct-task.c
@@ -76,9 +76,11 @@ ufo_flat_field_correct_task_setup (UfoTask *task,
 
 static void
 ufo_flat_field_correct_task_get_requisition (UfoTask *task,
-                                                UfoBuffer **inputs,
-                                                UfoRequisition *requisition)
+                                             UfoBuffer **inputs,
+                                             UfoRequisition *requisition,
+                                             GError **error)
 {
+    /* TODO: check the size is the same for all three inputs */
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
 
diff --git a/src/ufo-flatten-inplace-task.c b/src/ufo-flatten-inplace-task.c
index dde1621..920834c 100644
--- a/src/ufo-flatten-inplace-task.c
+++ b/src/ufo-flatten-inplace-task.c
@@ -69,7 +69,8 @@ ufo_flatten_inplace_task_setup (UfoTask *task,
 static void
 ufo_flatten_inplace_task_get_requisition (UfoTask *task,
                                           UfoBuffer **inputs,
-                                          UfoRequisition *requisition)
+                                          UfoRequisition *requisition,
+                                          GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-flatten-task.c b/src/ufo-flatten-task.c
index 6ec0fc3..36c45e7 100644
--- a/src/ufo-flatten-task.c
+++ b/src/ufo-flatten-task.c
@@ -75,7 +75,8 @@ ufo_flatten_task_setup (UfoTask *task,
 static void
 ufo_flatten_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
     requisition->n_dims = 2;
diff --git a/src/ufo-flip-task.c b/src/ufo-flip-task.c
index 6799e0e..088d0f0 100644
--- a/src/ufo-flip-task.c
+++ b/src/ufo-flip-task.c
@@ -78,7 +78,8 @@ ufo_flip_task_setup (UfoTask *task,
 static void
 ufo_flip_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-forwardproject-task.c b/src/ufo-forwardproject-task.c
index 3b729cd..6b59f9c 100644
--- a/src/ufo-forwardproject-task.c
+++ b/src/ufo-forwardproject-task.c
@@ -77,7 +77,8 @@ ufo_forwardproject_task_setup (UfoTask *task,
 static void
 ufo_forwardproject_task_get_requisition (UfoTask *task,
                                          UfoBuffer **inputs,
-                                         UfoRequisition *requisition)
+                                         UfoRequisition *requisition,
+                                         GError **error)
 {
     UfoForwardprojectTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-gemm-task.c b/src/ufo-gemm-task.c
index fcad5ef..eccbc0d 100644
--- a/src/ufo-gemm-task.c
+++ b/src/ufo-gemm-task.c
@@ -70,7 +70,8 @@ ufo_gemm_task_setup (UfoTask *task,
 static void
 ufo_gemm_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     UfoGemmTaskPrivate *priv;
     UfoRequisition r_A;
@@ -85,15 +86,17 @@ ufo_gemm_task_get_requisition (UfoTask *task,
     ufo_buffer_get_requisition (inputs[2], &r_C);
 
     if (r_B.dims[0] != r_A.dims[1]) {
-        g_warning ("A = <%zu, %zu> not compatible with B = <%zu, %zu>",
-                   r_A.dims[0], r_A.dims[1], r_B.dims[0], r_B.dims[0]);
+        g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                     "A = <%zu, %zu> not compatible with B = <%zu, %zu>",
+                     r_A.dims[0], r_A.dims[1], r_B.dims[0], r_B.dims[0]);
 
         priv->error = TRUE;
     }
 
     if ((r_C.dims[0] != r_A.dims[0]) || (r_C.dims[1] != r_B.dims[1])) {
-        g_warning ("C = <%zu, %zu> not compatible with A = <%zu, %zu> and B = <%zu, %zu>",
-                    r_C.dims[0], r_C.dims[1], r_A.dims[0], r_A.dims[1], r_B.dims[0], r_B.dims[1]);
+        g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                     "C = <%zu, %zu> not compatible with A = <%zu, %zu> and B = <%zu, %zu>",
+                     r_C.dims[0], r_C.dims[1], r_A.dims[0], r_A.dims[1], r_B.dims[0], r_B.dims[1]);
 
         priv->error = TRUE;
     }
diff --git a/src/ufo-get-dup-circ-task.c b/src/ufo-get-dup-circ-task.c
index 1c91b00..d0cc4ee 100644
--- a/src/ufo-get-dup-circ-task.c
+++ b/src/ufo-get-dup-circ-task.c
@@ -62,7 +62,8 @@ ufo_get_dup_circ_task_setup (UfoTask *task,
 static void
 ufo_get_dup_circ_task_get_requisition (UfoTask *task,
                                        UfoBuffer **inputs,
-                                       UfoRequisition *requisition)
+                                       UfoRequisition *requisition,
+                                       GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-gradient-task.c b/src/ufo-gradient-task.c
index b3e4824..ce3f878 100644
--- a/src/ufo-gradient-task.c
+++ b/src/ufo-gradient-task.c
@@ -70,8 +70,8 @@ ufo_gradient_task_new (void)
 
 static void
 ufo_gradient_task_setup (UfoTask *task,
-                       UfoResources *resources,
-                       GError **error)
+                         UfoResources *resources,
+                         GError **error)
 {
     UfoGradientTaskPrivate *priv = UFO_GRADIENT_TASK_GET_PRIVATE (task);
     priv->kernel = ufo_resources_get_kernel (resources, "gradient.cl",
@@ -83,7 +83,8 @@ ufo_gradient_task_setup (UfoTask *task,
 static void
 ufo_gradient_task_get_requisition (UfoTask *task,
                                    UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                   UfoRequisition *requisition,
+                                   GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-ifft-task.c b/src/ufo-ifft-task.c
index 9d665ad..6a7ede4 100644
--- a/src/ufo-ifft-task.c
+++ b/src/ufo-ifft-task.c
@@ -83,12 +83,19 @@ ufo_ifft_task_setup (UfoTask *task,
 static void
 ufo_ifft_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     UfoIfftTaskPrivate *priv;
     UfoRequisition in_req;
     cl_command_queue queue;
 
+    if (ufo_buffer_get_layout (inputs[0]) != UFO_BUFFER_LAYOUT_COMPLEX_INTERLEAVED) {
+        g_set_error_literal (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                             "ifft input must be complex");
+        return;
+    }
+
     priv = UFO_IFFT_TASK_GET_PRIVATE (task);
     ufo_buffer_get_requisition (inputs[0], &in_req);
 
diff --git a/src/ufo-interpolate-stream-task.c b/src/ufo-interpolate-stream-task.c
index f659972..f2a9ad7 100644
--- a/src/ufo-interpolate-stream-task.c
+++ b/src/ufo-interpolate-stream-task.c
@@ -75,7 +75,8 @@ ufo_interpolate_stream_task_setup (UfoTask *task,
 static void
 ufo_interpolate_stream_task_get_requisition (UfoTask *task,
                                              UfoBuffer **inputs,
-                                             UfoRequisition *requisition)
+                                             UfoRequisition *requisition,
+                                             GError **error)
 {
     /* TODO: check it's the same all the time */
     ufo_buffer_get_requisition (inputs[0], requisition);
diff --git a/src/ufo-interpolate-task.c b/src/ufo-interpolate-task.c
index d8f5dbc..a0d0725 100644
--- a/src/ufo-interpolate-task.c
+++ b/src/ufo-interpolate-task.c
@@ -76,7 +76,8 @@ ufo_interpolate_task_setup (UfoTask *task,
 static void
 ufo_interpolate_task_get_requisition (UfoTask *task,
                                       UfoBuffer **inputs,
-                                      UfoRequisition *requisition)
+                                      UfoRequisition *requisition,
+                                      GError **error)
 {
     /* TODO: check for input compatibility */
     ufo_buffer_get_requisition (inputs[0], requisition);
diff --git a/src/ufo-lamino-backproject-task.c b/src/ufo-lamino-backproject-task.c
index 4184595..a6e9863 100644
--- a/src/ufo-lamino-backproject-task.c
+++ b/src/ufo-lamino-backproject-task.c
@@ -243,7 +243,8 @@ ufo_lamino_backproject_task_setup (UfoTask *task,
 static void
 ufo_lamino_backproject_task_get_requisition (UfoTask *task,
                                              UfoBuffer **inputs,
-                                             UfoRequisition *requisition)
+                                             UfoRequisition *requisition,
+                                             GError **error)
 {
     UfoLaminoBackprojectTaskPrivate *priv;
     gfloat start, stop, step;
diff --git a/src/ufo-loop-task.c b/src/ufo-loop-task.c
index cd962e3..06054f1 100644
--- a/src/ufo-loop-task.c
+++ b/src/ufo-loop-task.c
@@ -58,7 +58,8 @@ ufo_loop_task_setup (UfoTask *task,
 static void
 ufo_loop_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-map-color-task.c b/src/ufo-map-color-task.c
index 8376c5b..c807d94 100644
--- a/src/ufo-map-color-task.c
+++ b/src/ufo-map-color-task.c
@@ -180,7 +180,8 @@ ufo_map_color_task_setup (UfoTask *task,
 static void
 ufo_map_color_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
     requisition->n_dims = 3;
diff --git a/src/ufo-map-slice-task.c b/src/ufo-map-slice-task.c
index 676e4a5..6b0df55 100644
--- a/src/ufo-map-slice-task.c
+++ b/src/ufo-map-slice-task.c
@@ -61,7 +61,8 @@ ufo_map_slice_task_setup (UfoTask *task,
 static void
 ufo_map_slice_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     UfoMapSliceTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-mask-task.c b/src/ufo-mask-task.c
index 2905eeb..0d99bd6 100644
--- a/src/ufo-mask-task.c
+++ b/src/ufo-mask-task.c
@@ -61,7 +61,8 @@ ufo_mask_task_setup (UfoTask *task,
 static void
 ufo_mask_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-measure-sharpness-task.c b/src/ufo-measure-sharpness-task.c
index ff86232..e1d47ba 100644
--- a/src/ufo-measure-sharpness-task.c
+++ b/src/ufo-measure-sharpness-task.c
@@ -57,7 +57,8 @@ ufo_measure_sharpness_task_setup (UfoTask *task,
 static void
 ufo_measure_sharpness_task_get_requisition (UfoTask *task,
                                             UfoBuffer **inputs,
-                                            UfoRequisition *requisition)
+                                            UfoRequisition *requisition,
+                                            GError **error)
 {
     requisition->n_dims = 0;
 }
diff --git a/src/ufo-measure-task.c b/src/ufo-measure-task.c
index 6ff975e..eff40fb 100644
--- a/src/ufo-measure-task.c
+++ b/src/ufo-measure-task.c
@@ -205,7 +205,8 @@ get_output_size (UfoMeasureTaskPrivate *priv,
 static void
 ufo_measure_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     UfoMeasureTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-median-filter-task.c b/src/ufo-median-filter-task.c
index 7972c4a..1467979 100644
--- a/src/ufo-median-filter-task.c
+++ b/src/ufo-median-filter-task.c
@@ -89,7 +89,8 @@ ufo_median_filter_task_setup (UfoTask *task,
 static void
 ufo_median_filter_task_get_requisition (UfoTask *task,
                                         UfoBuffer **inputs,
-                                        UfoRequisition *requisition)
+                                        UfoRequisition *requisition,
+                                        GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-memory-in-task.c b/src/ufo-memory-in-task.c
index 2ad9908..6be47f3 100644
--- a/src/ufo-memory-in-task.c
+++ b/src/ufo-memory-in-task.c
@@ -74,7 +74,8 @@ ufo_memory_in_task_setup (UfoTask *task,
 static void
 ufo_memory_in_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     UfoMemoryInTaskPrivate *priv;
 
diff --git a/src/ufo-memory-out-task.c b/src/ufo-memory-out-task.c
index f9d9421..e4ae9cf 100644
--- a/src/ufo-memory-out-task.c
+++ b/src/ufo-memory-out-task.c
@@ -75,7 +75,8 @@ ufo_memory_out_task_setup (UfoTask *task,
 static void
 ufo_memory_out_task_get_requisition (UfoTask *task,
                                      UfoBuffer **inputs,
-                                     UfoRequisition *requisition)
+                                     UfoRequisition *requisition,
+                                     GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-merge-task.c b/src/ufo-merge-task.c
index d6839d9..34112c8 100644
--- a/src/ufo-merge-task.c
+++ b/src/ufo-merge-task.c
@@ -63,7 +63,8 @@ ufo_merge_task_setup (UfoTask *task,
 static void
 ufo_merge_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     UfoMergeTaskPrivate *priv;
 
diff --git a/src/ufo-metaballs-task.c b/src/ufo-metaballs-task.c
index 656f3d7..32a4a42 100644
--- a/src/ufo-metaballs-task.c
+++ b/src/ufo-metaballs-task.c
@@ -112,7 +112,8 @@ ufo_metaballs_task_setup (UfoTask *task,
 static void
 ufo_metaballs_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     UfoMetaballsTaskPrivate *priv;
 
diff --git a/src/ufo-monitor-task.c b/src/ufo-monitor-task.c
index bbe549e..71b4cae 100644
--- a/src/ufo-monitor-task.c
+++ b/src/ufo-monitor-task.c
@@ -56,7 +56,8 @@ ufo_monitor_task_setup (UfoTask *task,
 static void
 ufo_monitor_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-null-task.c b/src/ufo-null-task.c
index 64ca347..c12babc 100644
--- a/src/ufo-null-task.c
+++ b/src/ufo-null-task.c
@@ -67,7 +67,8 @@ ufo_null_task_setup (UfoTask *task,
 static void
 ufo_null_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     requisition->n_dims = 0;
 }
diff --git a/src/ufo-opencl-reduce-task.c b/src/ufo-opencl-reduce-task.c
index be40233..787d178 100644
--- a/src/ufo-opencl-reduce-task.c
+++ b/src/ufo-opencl-reduce-task.c
@@ -134,7 +134,8 @@ ufo_opencl_reduce_task_setup (UfoTask *task,
 static void
 ufo_opencl_reduce_task_get_requisition (UfoTask *task,
                                         UfoBuffer **inputs,
-                                        UfoRequisition *requisition)
+                                        UfoRequisition *requisition,
+                                        GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-opencl-task.c b/src/ufo-opencl-task.c
index 84e7b36..53ef8b2 100644
--- a/src/ufo-opencl-task.c
+++ b/src/ufo-opencl-task.c
@@ -161,7 +161,8 @@ ufo_opencl_task_setup (UfoTask *task,
 static void
 ufo_opencl_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-ordfilt-task.c b/src/ufo-ordfilt-task.c
index 3efd689..fc1bed5 100644
--- a/src/ufo-ordfilt-task.c
+++ b/src/ufo-ordfilt-task.c
@@ -94,7 +94,8 @@ ufo_ordfilt_task_setup (UfoTask *task,
 static void
 ufo_ordfilt_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-pad-task.c b/src/ufo-pad-task.c
index 027f3fd..f012b24 100644
--- a/src/ufo-pad-task.c
+++ b/src/ufo-pad-task.c
@@ -102,7 +102,8 @@ ufo_pad_task_setup (UfoTask *task,
 static void
 ufo_pad_task_get_requisition (UfoTask *task,
                               UfoBuffer **inputs,
-                              UfoRequisition *requisition)
+                              UfoRequisition *requisition,
+                              GError **error)
 {
     UfoPadTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-polar-coordinates-task.c b/src/ufo-polar-coordinates-task.c
index 7d1ea5e..91a7303 100644
--- a/src/ufo-polar-coordinates-task.c
+++ b/src/ufo-polar-coordinates-task.c
@@ -108,7 +108,8 @@ ufo_polar_coordinates_task_setup (UfoTask *task,
 static void
 ufo_polar_coordinates_task_get_requisition (UfoTask *task,
                                             UfoBuffer **inputs,
-                                            UfoRequisition *requisition)
+                                            UfoRequisition *requisition,
+                                            GError **error)
 {
     UfoPolarCoordinatesTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-read-task.c b/src/ufo-read-task.c
index 91c33f8..04886fe 100644
--- a/src/ufo-read-task.c
+++ b/src/ufo-read-task.c
@@ -253,7 +253,8 @@ get_reader (UfoReadTaskPrivate *priv, const gchar *filename)
 static void
 ufo_read_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     UfoReadTaskPrivate *priv;
     const gchar *filename;
diff --git a/src/ufo-reduce-task.c b/src/ufo-reduce-task.c
index 7fb7384..54f64a0 100644
--- a/src/ufo-reduce-task.c
+++ b/src/ufo-reduce-task.c
@@ -53,7 +53,8 @@ ufo_reduce_task_setup (UfoTask *task,
 static void
 ufo_reduce_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     ufo_buffer_get_requisition(inputs[0], requisition);
     requisition->dims[0] /= 2;
diff --git a/src/ufo-refeed-task.c b/src/ufo-refeed-task.c
index 73ae07d..936b236 100644
--- a/src/ufo-refeed-task.c
+++ b/src/ufo-refeed-task.c
@@ -60,7 +60,8 @@ ufo_refeed_task_setup (UfoTask *task,
 static void
 ufo_refeed_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     UfoRefeedTaskPrivate *priv;
 
diff --git a/src/ufo-remove-circle-task.c b/src/ufo-remove-circle-task.c
index 52183ea..113d1ca 100644
--- a/src/ufo-remove-circle-task.c
+++ b/src/ufo-remove-circle-task.c
@@ -60,7 +60,8 @@ ufo_remove_circle_task_setup (UfoTask *task,
 static void
 ufo_remove_circle_task_get_requisition (UfoTask *task,
                                         UfoBuffer **inputs,
-                                        UfoRequisition *requisition)
+                                        UfoRequisition *requisition,
+                                        GError **error)
 {
     /* At most we will have same sized buffer as input since we are only
      * removing circles  */
diff --git a/src/ufo-remove-outliers-task.c b/src/ufo-remove-outliers-task.c
index 604f077..1bea083 100644
--- a/src/ufo-remove-outliers-task.c
+++ b/src/ufo-remove-outliers-task.c
@@ -76,8 +76,9 @@ ufo_remove_outliers_task_setup (UfoTask *task,
 
 static void
 ufo_remove_outliers_task_get_requisition (UfoTask *task,
-                                 UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                          UfoBuffer **inputs,
+                                          UfoRequisition *requisition,
+                                          GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-replicate-task.c b/src/ufo-replicate-task.c
index 98cb5cc..c9946d7 100644
--- a/src/ufo-replicate-task.c
+++ b/src/ufo-replicate-task.c
@@ -52,9 +52,10 @@ ufo_replicate_task_setup (UfoTask *task,
 static void
 ufo_replicate_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
-    ufo_buffer_get_requisition(inputs[0], requisition);
+    ufo_buffer_get_requisition (inputs[0], requisition);
 }
 
 static guint
diff --git a/src/ufo-rescale-task.c b/src/ufo-rescale-task.c
index 6025c5d..ff0ab34 100644
--- a/src/ufo-rescale-task.c
+++ b/src/ufo-rescale-task.c
@@ -102,8 +102,9 @@ ufo_rescale_task_setup (UfoTask *task,
 
 static void
 ufo_rescale_task_get_requisition (UfoTask *task,
-                                     UfoBuffer **inputs,
-                                     UfoRequisition *requisition)
+                                  UfoBuffer **inputs,
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     UfoRescaleTaskPrivate *priv;
     UfoRequisition in_req;
@@ -120,6 +121,7 @@ ufo_rescale_task_get_requisition (UfoTask *task,
     if (requisition->dims[0] == 0) {
         requisition->dims[0] = 1;
     }
+
     if (requisition->dims[1] == 0) {
         requisition->dims[1] = 1;
     }
diff --git a/src/ufo-retrieve-phase-task.c b/src/ufo-retrieve-phase-task.c
index 89a4429..a7595a9 100644
--- a/src/ufo-retrieve-phase-task.c
+++ b/src/ufo-retrieve-phase-task.c
@@ -138,12 +138,14 @@ ufo_retrieve_phase_task_setup (UfoTask *task,
 static void
 ufo_retrieve_phase_task_get_requisition (UfoTask *task,
                                          UfoBuffer **inputs,
-                                         UfoRequisition *requisition)
+                                         UfoRequisition *requisition,
+                                         GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 
     if (!IS_POW_OF_2 (requisition->dims[0]) || !IS_POW_OF_2 (requisition->dims[1])) {
-        g_error("Please, perform zeropadding of your dataset along both directions (width, height) up to length of power of 2 (e.g. 256, 512, 1024, 2048, etc.)");
+        g_set_error_literal (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                             "Please, perform zeropadding of your dataset along both directions (width, height) up to length of power of 2 (e.g. 256, 512, 1024, 2048, etc.)");
     }
 }
 
diff --git a/src/ufo-ring-pattern-task.c b/src/ufo-ring-pattern-task.c
index 09571b7..b8dcb54 100644
--- a/src/ufo-ring-pattern-task.c
+++ b/src/ufo-ring-pattern-task.c
@@ -72,8 +72,9 @@ ufo_ring_pattern_task_setup (UfoTask *task,
 
 static void
 ufo_ring_pattern_task_get_requisition (UfoTask *task,
-                                 UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                       UfoBuffer **inputs,
+                                       UfoRequisition *requisition,
+                                       GError **error)
 {
     UfoRingPatternTaskPrivate *priv = UFO_RING_PATTERN_TASK_GET_PRIVATE (task);
     requisition->dims[0] = priv->width;
diff --git a/src/ufo-ringwriter-task.c b/src/ufo-ringwriter-task.c
index 9cbc013..a9e4427 100644
--- a/src/ufo-ringwriter-task.c
+++ b/src/ufo-ringwriter-task.c
@@ -63,8 +63,9 @@ ufo_ringwriter_task_setup (UfoTask *task,
 
 static void
 ufo_ringwriter_task_get_requisition (UfoTask *task,
-                                 UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                     UfoBuffer **inputs,
+                                     UfoRequisition *requisition,
+                                     GError **error)
 {
     requisition->n_dims = 0;
 }
@@ -77,7 +78,7 @@ ufo_ringwriter_task_get_num_inputs (UfoTask *task)
 
 static guint
 ufo_ringwriter_task_get_num_dimensions (UfoTask *task,
-                                             guint input)
+                                        guint input)
 {
     return 1;
 }
diff --git a/src/ufo-rotate-task.c b/src/ufo-rotate-task.c
index 76cbe6f..eda4d87 100644
--- a/src/ufo-rotate-task.c
+++ b/src/ufo-rotate-task.c
@@ -143,7 +143,8 @@ ufo_rotate_task_setup (UfoTask *task,
 static void
 ufo_rotate_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     UfoRotateTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-segment-task.c b/src/ufo-segment-task.c
index 234fb94..2554731 100644
--- a/src/ufo-segment-task.c
+++ b/src/ufo-segment-task.c
@@ -124,7 +124,8 @@ ufo_segment_task_setup (UfoTask *task,
 static void
 ufo_segment_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     UfoRequisition label_req;
 
@@ -136,8 +137,10 @@ ufo_segment_task_get_requisition (UfoTask *task,
 
     if ((label_req.dims[0] != requisition->dims[0]) ||
         (label_req.dims[1] != requisition->dims[1])) {
-        g_warning ("Label field and input dimensions do not match ([%zu, %zu] != [%zu, %zu])",
-                   label_req.dims[0], label_req.dims[1], requisition->dims[0], requisition->dims[1]);
+
+        g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                     "Label field and input dimensions do not match ([%zu, %zu] != [%zu, %zu])",
+                     label_req.dims[0], label_req.dims[1], requisition->dims[0], requisition->dims[1]);
     }
 }
 
diff --git a/src/ufo-sleep-task.c b/src/ufo-sleep-task.c
index 2386bea..7c09074 100644
--- a/src/ufo-sleep-task.c
+++ b/src/ufo-sleep-task.c
@@ -62,7 +62,8 @@ ufo_sleep_task_setup (UfoTask *task,
 static void
 ufo_sleep_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-slice-task.c b/src/ufo-slice-task.c
index 9e1551d..0fc14fe 100644
--- a/src/ufo-slice-task.c
+++ b/src/ufo-slice-task.c
@@ -57,7 +57,8 @@ ufo_slice_task_setup (UfoTask *task,
 static void
 ufo_slice_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     UfoSliceTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-stack-task.c b/src/ufo-stack-task.c
index 46510ff..9270637 100644
--- a/src/ufo-stack-task.c
+++ b/src/ufo-stack-task.c
@@ -64,7 +64,8 @@ ufo_stack_task_setup (UfoTask *task,
 static void
 ufo_stack_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     UfoStackTaskPrivate *priv;
 
diff --git a/src/ufo-stamp-task.c b/src/ufo-stamp-task.c
index 4fbf63a..11ea90f 100644
--- a/src/ufo-stamp-task.c
+++ b/src/ufo-stamp-task.c
@@ -123,7 +123,8 @@ ufo_stamp_task_setup (UfoTask *task,
 static void
 ufo_stamp_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-stdin-task.c b/src/ufo-stdin-task.c
index b6e3dfd..c0d3a4e 100644
--- a/src/ufo-stdin-task.c
+++ b/src/ufo-stdin-task.c
@@ -64,7 +64,8 @@ ufo_stdin_task_setup (UfoTask *task,
 static void
 ufo_stdin_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     UfoStdinTaskPrivate *priv;
 
diff --git a/src/ufo-stitch-task.c b/src/ufo-stitch-task.c
index 9491f54..f935899 100644
--- a/src/ufo-stitch-task.c
+++ b/src/ufo-stitch-task.c
@@ -94,7 +94,8 @@ ufo_stitch_task_setup (UfoTask *task,
 static void
 ufo_stitch_task_get_requisition (UfoTask *task,
                                  UfoBuffer **inputs,
-                                 UfoRequisition *requisition)
+                                 UfoRequisition *requisition,
+                                 GError **error)
 {
     UfoStitchTaskPrivate *priv;
     UfoRequisition left_req, right_req;
@@ -103,8 +104,11 @@ ufo_stitch_task_get_requisition (UfoTask *task,
     ufo_buffer_get_requisition (inputs[0], &left_req);
     ufo_buffer_get_requisition (inputs[1], &right_req);
 
-    if (left_req.dims[1] != right_req.dims[1])
-        g_warning ("Both inputs must have the same height");
+    if (left_req.dims[1] != right_req.dims[1]) {
+        g_set_error_literal (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                             "Both stitch inputs must have the same height");
+        return;
+    }
 
     priv->overlap = (priv->shift >= 0) ? left_req.dims[0] - priv->shift : right_req.dims[0] + priv->shift;
     requisition->n_dims = 2;
diff --git a/src/ufo-subtract-task.c b/src/ufo-subtract-task.c
index 0f10797..a381de5 100644
--- a/src/ufo-subtract-task.c
+++ b/src/ufo-subtract-task.c
@@ -72,7 +72,8 @@ ufo_subtract_task_setup (UfoTask *task,
 static void
 ufo_subtract_task_get_requisition (UfoTask *task,
                                    UfoBuffer **inputs,
-                                   UfoRequisition *requisition)
+                                   UfoRequisition *requisition,
+                                   GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
 }
diff --git a/src/ufo-swap-quadrants-task.c b/src/ufo-swap-quadrants-task.c
index 5112831..0f786cc 100644
--- a/src/ufo-swap-quadrants-task.c
+++ b/src/ufo-swap-quadrants-task.c
@@ -67,7 +67,8 @@ ufo_swap_quadrants_task_setup (UfoTask *task,
 static void
 ufo_swap_quadrants_task_get_requisition (UfoTask *task,
                                          UfoBuffer **inputs,
-                                         UfoRequisition *requisition)
+                                         UfoRequisition *requisition,
+                                         GError **error)
 {
     UfoRequisition input_requisition;
     ufo_buffer_get_requisition (inputs[0], &input_requisition);
diff --git a/src/ufo-tile-task.c b/src/ufo-tile-task.c
index 1652f52..005d035 100644
--- a/src/ufo-tile-task.c
+++ b/src/ufo-tile-task.c
@@ -78,7 +78,8 @@ ufo_tile_task_setup (UfoTask *task,
 static void
 ufo_tile_task_get_requisition (UfoTask *task,
                                UfoBuffer **inputs,
-                               UfoRequisition *requisition)
+                               UfoRequisition *requisition,
+                               GError **error)
 {
     UfoTileTaskPrivate *priv;
     gsize in_width;
@@ -91,18 +92,22 @@ ufo_tile_task_get_requisition (UfoTask *task,
 
     if (priv->width > 0) {
         if (priv->width > in_width)
-            g_error ("tile: width %u cannot be larger than %zu", priv->width, in_width);
+            g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                         "tile: width %u cannot be larger than %zu", priv->width, in_width);
         else if (in_width % priv->width)
-            g_error ("tile: input width %zu must be a multiple of width %u", in_width, priv->width);
+            g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                         "tile: input width %zu must be a multiple of width %u", in_width, priv->width);
         else
             requisition->dims[0] = priv->width;
     }
 
     if (priv->height > 0) {
         if (priv->height > in_height)
-            g_error ("tile: height %u cannot be larger than %zu", priv->height, in_height);
+            g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                         "tile: height %u cannot be larger than %zu", priv->height, in_height);
         else if (requisition->dims[1] % priv->height)
-            g_error ("tile: input height %zu must be a multiple of height %u", in_height, priv->height);
+            g_set_error (error, UFO_TASK_ERROR, UFO_TASK_ERROR_GET_REQUISITION,
+                         "tile: input height %zu must be a multiple of height %u", in_height, priv->height);
         else
             requisition->dims[1] = priv->height;
     }
diff --git a/src/ufo-transpose-projections-task.c b/src/ufo-transpose-projections-task.c
index f3ce3cc..c4780ae 100644
--- a/src/ufo-transpose-projections-task.c
+++ b/src/ufo-transpose-projections-task.c
@@ -125,8 +125,9 @@ ufo_transpose_projections_task_setup (UfoTask *task,
 
 static void
 ufo_transpose_projections_task_get_requisition (UfoTask *task,
-                                         UfoBuffer **inputs,
-                                         UfoRequisition *requisition)
+                                                UfoBuffer **inputs,
+                                                UfoRequisition *requisition,
+                                                GError **error)
 {
     UfoTransposeProjectionsTaskPrivate *priv;
     UfoRequisition in_req;
diff --git a/src/ufo-transpose-task.c b/src/ufo-transpose-task.c
index d28a576..3a9130b 100644
--- a/src/ufo-transpose-task.c
+++ b/src/ufo-transpose-task.c
@@ -58,7 +58,8 @@ ufo_transpose_task_setup (UfoTask *task,
 static void
 ufo_transpose_task_get_requisition (UfoTask *task,
                                     UfoBuffer **inputs,
-                                    UfoRequisition *requisition)
+                                    UfoRequisition *requisition,
+                                    GError **error)
 {
     UfoRequisition in_req;
 
diff --git a/src/ufo-unsplit-task.c b/src/ufo-unsplit-task.c
index cc2dbf9..54d559b 100644
--- a/src/ufo-unsplit-task.c
+++ b/src/ufo-unsplit-task.c
@@ -61,7 +61,8 @@ ufo_unsplit_task_setup (UfoTask *task,
 static void
 ufo_unsplit_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     ufo_buffer_get_requisition (inputs[0], requisition);
     requisition->n_dims = 2;
diff --git a/src/ufo-volume-render-task.c b/src/ufo-volume-render-task.c
index 21bcfe5..c6393d0 100644
--- a/src/ufo-volume-render-task.c
+++ b/src/ufo-volume-render-task.c
@@ -113,7 +113,8 @@ ufo_volume_render_task_setup (UfoTask *task,
 static void
 ufo_volume_render_task_get_requisition (UfoTask *task,
                                         UfoBuffer **inputs,
-                                        UfoRequisition *requisition)
+                                        UfoRequisition *requisition,
+                                        GError **error)
 {
     UfoVolumeRenderTaskPrivate *priv;
 
diff --git a/src/ufo-write-task.c b/src/ufo-write-task.c
index d3c5027..80f4c5c 100644
--- a/src/ufo-write-task.c
+++ b/src/ufo-write-task.c
@@ -262,7 +262,8 @@ ufo_write_task_setup (UfoTask *task,
 static void
 ufo_write_task_get_requisition (UfoTask *task,
                                 UfoBuffer **inputs,
-                                UfoRequisition *requisition)
+                                UfoRequisition *requisition,
+                                GError **error)
 {
     requisition->n_dims = 0;
 }
diff --git a/src/ufo-zeropad-task.c b/src/ufo-zeropad-task.c
index 32b2ad1..ea823dc 100644
--- a/src/ufo-zeropad-task.c
+++ b/src/ufo-zeropad-task.c
@@ -79,8 +79,9 @@ ufo_zeropad_task_setup (UfoTask *task,
 
 static void
 ufo_zeropad_task_get_requisition (UfoTask *task,
-                                      UfoBuffer **inputs,
-                                      UfoRequisition *requisition)
+                                  UfoBuffer **inputs,
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     UfoZeropadTaskPrivate *priv = UFO_ZEROPAD_TASK_GET_PRIVATE (task);
 
diff --git a/src/ufo-zmq-pub-task.c b/src/ufo-zmq-pub-task.c
index a9beed0..8b11a02 100644
--- a/src/ufo-zmq-pub-task.c
+++ b/src/ufo-zmq-pub-task.c
@@ -145,7 +145,8 @@ ufo_zmq_pub_task_setup (UfoTask *task,
 static void
 ufo_zmq_pub_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     requisition->n_dims = 0;
 }
diff --git a/src/ufo-zmq-sub-task.c b/src/ufo-zmq-sub-task.c
index 1145272..5c8f7e5 100644
--- a/src/ufo-zmq-sub-task.c
+++ b/src/ufo-zmq-sub-task.c
@@ -170,7 +170,8 @@ request_data (UfoZmqSubTaskPrivate *priv)
 static void
 ufo_zmq_sub_task_get_requisition (UfoTask *task,
                                   UfoBuffer **inputs,
-                                  UfoRequisition *requisition)
+                                  UfoRequisition *requisition,
+                                  GError **error)
 {
     UfoZmqSubTaskPrivate *priv;
     zmq_msg_t htype_msg;
@@ -178,7 +179,6 @@ ufo_zmq_sub_task_get_requisition (UfoTask *task,
     JsonParser *parser;
     JsonObject *object;
     JsonArray *array;
-    GError *error = NULL;
 
     priv = UFO_ZMQ_SUB_TASK_GET_PRIVATE (task);
 
@@ -189,11 +189,8 @@ ufo_zmq_sub_task_get_requisition (UfoTask *task,
     zmq_msg_recv (&htype_msg, priv->socket, 0);
     header = zmq_msg_data (&htype_msg);
     parser = json_parser_new_immutable ();
-    json_parser_load_from_data (parser, header, zmq_msg_size (&htype_msg), &error);
 
-    if (error != NULL) {
-        g_error ("Error parsing JSON: %s", error->message);
-        g_error_free (error);
+    if (!json_parser_load_from_data (parser, header, zmq_msg_size (&htype_msg), error)) {
         g_object_unref (parser);
         return;
     }