m.nviz.image: Check return value from GS_write_(ppm|tif)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@72948 15284696-431f-4ddb-bdfa-cd5b030d7da7

misc/m.nviz.image/main.c

@@ -236,7 +236,9 @@ int main(int argc, char *argv[])
     if (strcmp(params->format->answer, "tif") == 0)
 	ret = write_img(output_name, FORMAT_TIF);
 
-    if (!ret)
+    if (ret == 1)
+	G_fatal_error(_("Failed to write image"));
+    else if (ret == 2)
 	G_fatal_error(_("Unsupported output format"));
 
     G_done_msg(_("File <%s> created."), output_name);

misc/m.nviz.image/write_img.c

@@ -23,19 +23,20 @@
 
    \param name filename
 
-   \return 1 on success
-   \return 0 on failure (unsupported format)
+   \return 0 on success
+   \return 1 on failure (failed to write image)
+   \return 2 on failure (unsupported format)
  */
 int write_img(const char *name, int format)
 {
     if (format == FORMAT_PPM)
-	GS_write_ppm(name);
+	return !GS_write_ppm(name);
 #ifdef HAVE_TIFFIO_H
     else if (format == FORMAT_TIF)
-	GS_write_tif(name);
+	return !GS_write_tif(name);
 #endif
     else
-	return 0;
+	return 2;
 
-    return 1;
+    return 0;
 }