diff --git a/CMakeLists.txt b/CMakeLists.txt
index a650eaf..a0fc088 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,5 @@
 cmake_minimum_required(VERSION 2.6)
 include(CheckIncludeFiles)
-include(CheckSymbolExists)
-include(CheckCSourceCompiles)
 
 project(foug_datax C)
 
@@ -17,19 +15,6 @@ check_include_files(stdint.h HAVE_STDINT_H)
 configure_file(src/c/config.h.cmake config.h @ONLY)
 include_directories(${CMAKE_BINARY_DIR}) # For generated "config.h"
 
-# Have fabsf() ?
-#check_symbol_exists(fabs  "math.h" HAVE_FABS)
-#check_symbol_exists(fabsf "math.h" HAVE_FABSF)
-
-#check_c_source_compiles("
-#                         #include <math.h>
-#                         int main()
-#                         {
-#                           fabsf(-1);
-#                           return 0;
-#                         }"
-#                         HAVE_FABSF)
-
 # Specific flags for gcc
 if(CMAKE_COMPILER_IS_GNUCC)
   set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -ansi -pedantic-errors -fstrict-aliasing")
diff --git a/qmake.build/c/libstl/libstl.pro b/qmake.build/c/libstl/libstl.pro
index dbcd6dc..98fc31a 100644
--- a/qmake.build/c/libstl/libstl.pro
+++ b/qmake.build/c/libstl/libstl.pro
@@ -31,7 +31,8 @@ HEADERS += \
     ../../../src/c/libstl/stlb_read.h \
     ../../../src/c/libstl/stlb_write.h \
     ../../../src/c/libstl/stl_triangle.h \
-    ../../../src/c/libstl/stlb_triangle.h
+    ../../../src/c/libstl/stlb_triangle.h \
+    ../../../src/c/error.h
 
 SOURCES += \
     ../../../src/c/endian.c \
@@ -39,7 +40,8 @@ SOURCES += \
     ../../../src/c/task_control.c \
     ../../../src/c/libstl/stla_read.c \
     ../../../src/c/libstl/stlb_read.c \
-    ../../../src/c/libstl/stlb_write.c
+    ../../../src/c/libstl/stlb_write.c \
+    ../../../src/c/error.c
 
 *-g++*:QMAKE_CFLAGS += -ansi -pedantic-errors
 *-msvc*:QMAKE_CFLAGS += -TC
diff --git a/src/c/error.c b/src/c/error.c
new file mode 100644
index 0000000..06df6a3
--- /dev/null
+++ b/src/c/error.c
@@ -0,0 +1,11 @@
+#include "error.h"
+
+foug_bool_t foug_datax_no_error(int code)
+{
+  return code == FOUG_DATAX_NO_ERROR;
+}
+
+foug_bool_t foug_datax_error(int code)
+{
+  return code != FOUG_DATAX_NO_ERROR;
+}
diff --git a/src/c/error.h b/src/c/error.h
new file mode 100644
index 0000000..fa5520a
--- /dev/null
+++ b/src/c/error.h
@@ -0,0 +1,16 @@
+#ifndef FOUG_C_DATAX_ERROR_H
+#define FOUG_C_DATAX_ERROR_H
+
+#include "global.h"
+
+/* Common errors */
+#define FOUG_DATAX_NO_ERROR                    0
+#define FOUG_DATAX_NULL_BUFFER_ERROR          -1
+#define FOUG_DATAX_INVALID_BUFFER_SIZE_ERROR  -2
+#define FOUG_DATAX_STREAM_ERROR               -3
+#define FOUG_DATAX_TASK_STOPPED_ERROR         -4
+
+FOUG_LIB_EXPORT foug_bool_t foug_datax_no_error(int code);
+FOUG_LIB_EXPORT foug_bool_t foug_datax_error(int code);
+
+#endif /* FOUG_C_DATAX_ERROR_H */
diff --git a/src/c/libstl/stla_read.c b/src/c/libstl/stla_read.c
index bad7d1c..e8478e4 100644
--- a/src/c/libstl/stla_read.c
+++ b/src/c/libstl/stla_read.c
@@ -1,5 +1,7 @@
 #include "stla_read.h"
 
+#include "../error.h"
+
 #include <ctype.h> /* isspace() */
 #include <errno.h>
 #include <stdlib.h>
@@ -15,7 +17,6 @@ typedef struct foug_stream_fwd_iterator
 
   void* cookie;
   void (*stream_read_hook)(const struct foug_stream_fwd_iterator* it);
-
 } foug_stream_fwd_iterator_t;
 
 static void foug_stream_fwd_iterator_read_hook(const foug_stream_fwd_iterator_t* it)
@@ -221,7 +222,6 @@ static int eat_facet(foug_stream_fwd_iterator_t* it,
 
 int foug_stla_read(foug_stla_read_args_t *args)
 {
-  foug_task_progress_t progress;
   char fixed_buffer[FOUG_STLA_READ_STRING_BUFFER_LEN];
   foug_string_buffer_t string_buffer;
   foug_stl_triangle_t triangle;
@@ -229,9 +229,9 @@ int foug_stla_read(foug_stla_read_args_t *args)
   int eat_facet_result;
 
   if (args->buffer == NULL)
-    return FOUG_STLA_READ_NULL_BUFFER;
+    return FOUG_DATAX_NULL_BUFFER_ERROR;
   if (args->buffer_size == 0)
-    return FOUG_STLA_READ_INVALID_BUFFER_SIZE_ERROR;
+    return FOUG_DATAX_INVALID_BUFFER_SIZE_ERROR;
 
   it.stream = &(args->stream);
   it.buffer = args->buffer;
@@ -246,11 +246,6 @@ int foug_stla_read(foug_stla_read_args_t *args)
   string_buffer.max_len = FOUG_STLA_READ_STRING_BUFFER_LEN;
   string_buffer.len = 0;
 
-  progress.range_min = 0.f;
-  progress.range_max = (foug_real32_t)args->data_size_hint;
-  progress.value = 0.f;
-  args->task_control.is_stop_requested = 0;
-
   /* Eat solids */
   while (eat_token(&it, "solid") == 0) {
     /* Try to eat solid's name */
@@ -283,5 +278,5 @@ int foug_stla_read(foug_stla_read_args_t *args)
     }
   }
 
-  return FOUG_STLA_READ_NO_ERROR;
+  return FOUG_DATAX_NO_ERROR;
 }
diff --git a/src/c/libstl/stla_read.h b/src/c/libstl/stla_read.h
index f6e5e49..dd5d2ba 100644
--- a/src/c/libstl/stla_read.h
+++ b/src/c/libstl/stla_read.h
@@ -3,6 +3,7 @@
 
 #include "stl_global.h"
 #include "stl_triangle.h"
+#include "../error.h"
 #include "../stream.h"
 #include "../task_control.h"
 
@@ -31,18 +32,7 @@ typedef struct foug_stla_read_args
 FOUG_DATAX_LIBSTL_EXPORT
 int foug_stla_read(foug_stla_read_args_t* args);
 
-#define FOUG_DATAX_NO_ERROR                    0
-#define FOUG_DATAX_NULL_BUFFER                -1
-#define FOUG_DATAX_INVALID_BUFFER_SIZE_ERROR  -2
-#define FOUG_DATAX_STREAM_ERROR               -3
-#define FOUG_DATAX_TASK_STOPPED_ERROR          -4
-
-/* Error codes returned by foug_stlb_read() */
-#define FOUG_STLA_READ_NO_ERROR                  0
-#define FOUG_STLA_READ_NULL_BUFFER               3
-#define FOUG_STLA_READ_INVALID_BUFFER_SIZE_ERROR 4
-#define FOUG_STLA_READ_PARSE_ERROR               5
-#define FOUG_STLA_READ_STREAM_ERROR              7
-#define FOUG_STLA_READ_TASK_STOPPED_ERROR        8
+/* Error codes returned by foug_stla_read() */
+#define FOUG_STLA_READ_PARSE_ERROR  1
 
 #endif /* FOUG_C_LIBSTL_STLA_READ_H */
diff --git a/src/c/libstl/stlb_read.c b/src/c/libstl/stlb_read.c
index 2df7710..bfd629f 100644
--- a/src/c/libstl/stlb_read.c
+++ b/src/c/libstl/stlb_read.c
@@ -1,12 +1,8 @@
 #include "stlb_read.h"
 
+#include "../error.h"
 #include "../endian.h"
 
-static foug_bool_t foug_stlb_no_error(int code)
-{
-  return code == FOUG_STLB_READ_NO_ERROR;
-}
-
 static void foug_stlb_read_facets(foug_stlb_geom_input_t* geom_input,
                                   uint8_t* buffer,
                                   uint32_t facet_count)
@@ -31,7 +27,7 @@ static void foug_stlb_read_facets(foug_stlb_geom_input_t* geom_input,
 
 int foug_stlb_read(foug_stlb_read_args_t *args)
 {
-  foug_task_progress_t progress;
+  uint8_t progress_pc;
   uint8_t header_data[FOUG_STLB_HEADER_SIZE];
   uint32_t total_facet_count;
   size_t buffer_facet_count;
@@ -40,9 +36,9 @@ int foug_stlb_read(foug_stlb_read_args_t *args)
   size_t facet_count_read;
 
   if (args->buffer == NULL)
-    return FOUG_STLB_READ_NULL_BUFFER;
+    return FOUG_DATAX_NULL_BUFFER_ERROR;
   if (args->buffer_size < FOUG_STLB_MIN_CONTENTS_SIZE)
-    return FOUG_STLB_READ_INVALID_BUFFER_SIZE_ERROR;
+    return FOUG_DATAX_INVALID_BUFFER_SIZE_ERROR;
 
   /* Read header */
   if (foug_stream_read(&args->stream, header_data, 1, FOUG_STLB_HEADER_SIZE) != FOUG_STLB_HEADER_SIZE)
@@ -59,42 +55,33 @@ int foug_stlb_read(foug_stlb_read_args_t *args)
   if (args->geom_input.begin_triangles_func != NULL)
     args->geom_input.begin_triangles_func(&args->geom_input, total_facet_count);
 
-  progress.range_min = 0.f;
-  progress.range_max = (foug_real32_t)total_facet_count;
-  progress.value = 0.f;
-  args->task_control.is_stop_requested = 0;
-
   /* Read triangles */
   buffer_facet_count = args->buffer_size / FOUG_STLB_TRIANGLE_SIZE;
   accum_facet_count_read = 0;
-  error = FOUG_STLB_READ_NO_ERROR;
-  while (foug_stlb_no_error(error) && accum_facet_count_read < total_facet_count) {
+  error = FOUG_DATAX_NO_ERROR;
+  while (foug_datax_no_error(error) && accum_facet_count_read < total_facet_count) {
     facet_count_read = foug_stream_read(&args->stream,
                                         args->buffer, FOUG_STLB_TRIANGLE_SIZE, buffer_facet_count);
     if (foug_stream_error(&args->stream) != 0)
-      error = FOUG_STLB_READ_STREAM_ERROR;
+      error = FOUG_DATAX_STREAM_ERROR;
     else if (facet_count_read > 0)
-      error = FOUG_STLB_READ_NO_ERROR;
+      error = FOUG_DATAX_NO_ERROR;
     else
       break; /* Exit if no facet to read */
 
-    if (foug_stlb_no_error(error)) {
+    if (foug_datax_no_error(error)) {
       foug_stlb_read_facets(&args->geom_input, args->buffer, facet_count_read);
       accum_facet_count_read += facet_count_read;
-      if (args->task_control.is_stop_requested) {
-        error = FOUG_STLB_READ_TASK_STOPPED_ERROR;
-        foug_task_control_handle_stop(&args->task_control);
-      }
-      else {
-        foug_task_control_set_progress(&args->task_control, &progress, accum_facet_count_read);
-      }
+      progress_pc = foug_percentage(0, total_facet_count, accum_facet_count_read);
+      if (!foug_task_control_handle_progress(&args->task_control, progress_pc))
+        error = FOUG_DATAX_TASK_STOPPED_ERROR;
     }
   } /* end while */
 
-  if (foug_stlb_no_error(error) && args->geom_input.end_triangles_func != NULL)
+  if (foug_datax_no_error(error) && args->geom_input.end_triangles_func != NULL)
     args->geom_input.end_triangles_func(&args->geom_input);
 
-  if (foug_stlb_no_error(error) && accum_facet_count_read != total_facet_count)
+  if (foug_datax_no_error(error) && accum_facet_count_read != total_facet_count)
     error = FOUG_STLB_READ_FACET_COUNT_ERROR;
   return error;
 }
diff --git a/src/c/libstl/stlb_read.h b/src/c/libstl/stlb_read.h
index 18513ad..2609e9e 100644
--- a/src/c/libstl/stlb_read.h
+++ b/src/c/libstl/stlb_read.h
@@ -3,6 +3,7 @@
 
 #include "stl_global.h"
 #include "stlb_triangle.h"
+#include "../error.h"
 #include "../stream.h"
 #include "../task_control.h"
 
@@ -31,12 +32,7 @@ FOUG_DATAX_LIBSTL_EXPORT
 int foug_stlb_read(foug_stlb_read_args_t* args);
 
 /* Error codes returned by foug_stlb_read() */
-#define FOUG_STLB_READ_NO_ERROR                  0
-#define FOUG_STLB_READ_NULL_BUFFER               3
-#define FOUG_STLB_READ_INVALID_BUFFER_SIZE_ERROR 4
-#define FOUG_STLB_READ_HEADER_WRONG_SIZE_ERROR   5
-#define FOUG_STLB_READ_FACET_COUNT_ERROR         6
-#define FOUG_STLB_READ_STREAM_ERROR              7
-#define FOUG_STLB_READ_TASK_STOPPED_ERROR        8
+#define FOUG_STLB_READ_HEADER_WRONG_SIZE_ERROR   1
+#define FOUG_STLB_READ_FACET_COUNT_ERROR         2
 
 #endif /* FOUG_C_LIBSTL_STLB_READ_H */
diff --git a/src/c/libstl/stlb_write.c b/src/c/libstl/stlb_write.c
index 559dae4..7635936 100644
--- a/src/c/libstl/stlb_write.c
+++ b/src/c/libstl/stlb_write.c
@@ -1,14 +1,9 @@
 #include "stlb_write.h"
 
-#include "stlb_triangle.h"
 #include "../endian.h"
+#include "../error.h"
 #include <string.h>
 
-static foug_bool_t foug_stlb_no_error(int code)
-{
-  return code == FOUG_STLB_WRITE_NO_ERROR;
-}
-
 static void foug_stlb_write_facets(const foug_stlb_geom_output_t* geom_output,
                                    uint8_t* buffer,
                                    uint32_t ifacet_start,
@@ -32,7 +27,6 @@ static void foug_stlb_write_facets(const foug_stlb_geom_output_t* geom_output,
 
 int foug_stlb_write(foug_stlb_write_args_t *args)
 {
-  foug_task_progress_t progress;
   uint8_t header_data[FOUG_STLB_HEADER_SIZE];
   uint32_t facet_count;
   uint32_t i_facet;
@@ -41,9 +35,9 @@ int foug_stlb_write(foug_stlb_write_args_t *args)
   int error;
 
   if (args->buffer == NULL)
-    return FOUG_STLB_WRITE_NULL_BUFFER_ERROR;
+    return FOUG_DATAX_NULL_BUFFER_ERROR;
   if (args->buffer_size < FOUG_STLB_MIN_CONTENTS_SIZE)
-    return FOUG_STLB_WRITE_INVALID_BUFFER_SIZE_ERROR;
+    return FOUG_DATAX_INVALID_BUFFER_SIZE_ERROR;
   if (args->geom_output.get_triangle_count_func == NULL)
     return FOUG_STLB_WRITE_NULL_GET_TRIANGLE_COUNT_FUNC;
   if (args->geom_output.get_triangle_func == NULL)
@@ -56,26 +50,21 @@ int foug_stlb_write(foug_stlb_write_args_t *args)
     memset(header_data, 0, FOUG_STLB_HEADER_SIZE);
 
   if (foug_stream_write(&args->stream, header_data, FOUG_STLB_HEADER_SIZE, 1) != 1)
-    return FOUG_STLB_WRITE_STREAM_ERROR;
+    return FOUG_DATAX_STREAM_ERROR;
 
   /* Write facet count */
   facet_count = args->geom_output.get_triangle_count_func(&args->geom_output);
   foug_encode_uint32_le(facet_count, args->buffer);
   if (foug_stream_write(&args->stream, args->buffer, sizeof(uint32_t), 1) != 1)
-    return FOUG_STLB_WRITE_STREAM_ERROR;
-
-  progress.range_min = 0.f;
-  progress.range_max = (foug_real32_t)facet_count;
-  progress.value = 0.f;
-  args->task_control.is_stop_requested = 0;
+    return FOUG_DATAX_STREAM_ERROR;
 
   /* Write triangles */
-  error = FOUG_STLB_WRITE_NO_ERROR;
+  error = FOUG_DATAX_NO_ERROR;
 
   buffer_facet_count = args->buffer_size / FOUG_STLB_TRIANGLE_SIZE;
   ifacet_start = 0;
   for (i_facet = 0;
-       i_facet < facet_count && foug_stlb_no_error(error);
+       i_facet < facet_count && foug_datax_no_error(error);
        i_facet += buffer_facet_count)
   {
     /* Write to buffer */
@@ -88,17 +77,15 @@ int foug_stlb_write(foug_stlb_write_args_t *args)
     if (foug_stream_write(&args->stream, args->buffer, FOUG_STLB_TRIANGLE_SIZE, buffer_facet_count)
         != buffer_facet_count)
     {
-      error = FOUG_STLB_WRITE_STREAM_ERROR;
+      error = FOUG_DATAX_STREAM_ERROR;
     }
 
     /* Task control */
-    if (foug_stlb_no_error(error)) {
-      if (args->task_control.is_stop_requested) {
-        foug_task_control_handle_stop(&args->task_control);
-        error = FOUG_STLB_WRITE_TASK_STOPPED_ERROR;
-      }
-      else {
-        foug_task_control_set_progress(&args->task_control, &progress, i_facet + 1);
+    if (foug_datax_no_error(error)) {
+      if (!foug_task_control_handle_progress(&args->task_control,
+                                             foug_percentage(0, facet_count, i_facet + 1)))
+      {
+        error = FOUG_DATAX_TASK_STOPPED_ERROR;
       }
     }
   } /* end for */
diff --git a/src/c/libstl/stlb_write.h b/src/c/libstl/stlb_write.h
index 39e3db7..6bdcb5f 100644
--- a/src/c/libstl/stlb_write.h
+++ b/src/c/libstl/stlb_write.h
@@ -3,6 +3,7 @@
 
 #include "stl_global.h"
 #include "stlb_triangle.h"
+#include "../error.h"
 #include "../stream.h"
 #include "../task_control.h"
 
@@ -30,12 +31,7 @@ FOUG_DATAX_LIBSTL_EXPORT
 int foug_stlb_write(foug_stlb_write_args_t* args);
 
 /* Error codes returned by foug_stlb_write() */
-#define FOUG_STLB_WRITE_NO_ERROR                     0
-#define FOUG_STLB_WRITE_NULL_BUFFER_ERROR            3
-#define FOUG_STLB_WRITE_NULL_GET_TRIANGLE_COUNT_FUNC 4
-#define FOUG_STLB_WRITE_NULL_GET_TRIANGLE_FUNC       5
-#define FOUG_STLB_WRITE_STREAM_ERROR                 6
-#define FOUG_STLB_WRITE_TASK_STOPPED_ERROR           7
-#define FOUG_STLB_WRITE_INVALID_BUFFER_SIZE_ERROR    8
+#define FOUG_STLB_WRITE_NULL_GET_TRIANGLE_COUNT_FUNC 1
+#define FOUG_STLB_WRITE_NULL_GET_TRIANGLE_FUNC       2
 
 #endif /* FOUG_C_LIBSTL_STLB_WRITE_H */
diff --git a/src/c/task_control.c b/src/c/task_control.c
index dadd5d8..1315dec 100644
--- a/src/c/task_control.c
+++ b/src/c/task_control.c
@@ -3,37 +3,20 @@
 #include <math.h>
 #include <string.h>
 
-/* foug_task_control */
-
-foug_real32_t foug_task_progress_get_value_pc(const foug_task_progress_t *progress)
+foug_bool_t foug_task_control_handle_progress(foug_task_control_t* ctrl, uint8_t progress_pc)
 {
-  if (progress == NULL)
-    return 0.f;
-  return fabs((progress->value - progress->range_min) / (progress->range_max - progress->range_min));
+  if (ctrl != NULL && ctrl->handle_progress_func != NULL)
+    return ctrl->handle_progress_func(ctrl, progress_pc);
+  return 1;
 }
 
-FOUG_LIB_EXPORT void foug_task_control_set_progress(foug_task_control_t* ctrl,
-                                                    foug_task_progress_t *progress,
-                                                    foug_real32_t value)
+uint8_t foug_percentage(size_t range_min, size_t range_max, size_t value)
 {
-  progress->value = value;
-  if (ctrl->handle_progress_update_func != NULL)
-    ctrl->handle_progress_update_func(ctrl, progress);
-}
-
-/* Task stop */
-
-void foug_task_control_async_stop(foug_task_control_t* ctrl)
-{
-  if (ctrl != NULL)
-    ctrl->is_stop_requested = 1;
-}
-
-void foug_task_control_handle_stop(foug_task_control_t* ctrl)
-{
-  if (ctrl != NULL) {
-    ctrl->is_stop_requested = 0;
-    if (ctrl->handle_stop_func != NULL)
-      ctrl->handle_stop_func(ctrl);
-  }
+  if (value >= range_max)
+    return 100;
+  else if (value <= range_min)
+    return 0;
+  else if (range_min < range_max)
+    return (value * 100) / (range_max - range_min);
+  return 0;
 }
diff --git a/src/c/task_control.h b/src/c/task_control.h
index 7315eb4..32e609d 100644
--- a/src/c/task_control.h
+++ b/src/c/task_control.h
@@ -4,33 +4,18 @@
 #include "global.h"
 #include "memory.h"
 
-/* foug_task_progress */
-typedef struct foug_task_progress
-{
-  foug_real32_t range_min;
-  foug_real32_t range_max;
-  foug_real32_t value;
-} foug_task_progress_t;
-
-/* Progress */
-FOUG_LIB_EXPORT foug_real32_t foug_task_progress_get_value_pc(const foug_task_progress_t* progress);
-
 /* foug_task_control */
 typedef struct foug_task_control foug_task_control_t;
 struct foug_task_control
 {
-  foug_bool_t is_stop_requested;
   void* cookie;
-  void (*handle_stop_func)(foug_task_control_t*);
-  void (*handle_progress_update_func)(foug_task_control_t*, const foug_task_progress_t*);
+  foug_bool_t (*handle_progress_func)(foug_task_control_t*, uint8_t);
 };
 
-FOUG_LIB_EXPORT void foug_task_control_set_progress(foug_task_control_t* ctrl,
-                                                    foug_task_progress_t* progress,
-                                                    foug_real32_t value);
+FOUG_LIB_EXPORT
+foug_bool_t foug_task_control_handle_progress(foug_task_control_t* ctrl, uint8_t progress_pc);
 
-/* Task stop */
-FOUG_LIB_EXPORT void foug_task_control_async_stop(foug_task_control_t* ctrl);
-FOUG_LIB_EXPORT void foug_task_control_handle_stop(foug_task_control_t* ctrl);
+FOUG_LIB_EXPORT
+uint8_t foug_percentage(size_t range_min, size_t range_max, size_t value);
 
 #endif /* FOUG_C_TASK_CONTROL_H */