normalize example exit status

Use EXIT_SUCCESS / EXIT_FAILURE in most cases as more granularity isn't
useful. For anim_diff, use 0 (success), 1 (image difference) and 2
(error) to align it with other diff utilities (diff, etc.).

Bug: webp:637
Change-Id: I52925de8622a5a4d2141883279d69a1d95ef9b12

examples/anim_diff.c

@@ -16,7 +16,7 @@
 #include <assert.h>
 #include <limits.h>
 #include <stdio.h>
-#include <stdlib.h>  // for 'strtod'.
+#include <stdlib.h>
 #include <string.h>  // for 'strcmp'.
 
 #include "./anim_util.h"
@@ -206,8 +206,9 @@ static void Help(void) {
   printf("  -version ............ print version number and exit\n");
 }
 
+// Returns 0 on success, 1 if animation files differ, and 2 for any error.
 int main(int argc, const char* argv[]) {
-  int return_code = -1;
+  int return_code = 2;
   int dump_frames = 0;
   const char* dump_folder = NULL;
   double min_psnr = 0.;
@@ -269,18 +270,18 @@ int main(int argc, const char* argv[]) {
     }
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(return_code);
     }
   }
   if (argc < 3) {
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(return_code);
   }
 
 
   if (!got_input2) {
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(return_code);
   }
 
   if (dump_frames) {
@@ -293,7 +294,7 @@ int main(int argc, const char* argv[]) {
     if (!ReadAnimatedImage(files[i], &images[i], dump_frames, dump_folder)) {
       WFPRINTF(stderr, "Error decoding file: %s\n Aborting.\n",
                (const W_CHAR*)files[i]);
-      return_code = -2;
+      return_code = 2;
       goto End;
     } else {
       MinimizeAnimationFrames(&images[i], max_diff);
@@ -304,7 +305,7 @@ int main(int argc, const char* argv[]) {
                                 premultiply, min_psnr)) {
     WFPRINTF(stderr, "\nFiles %s and %s differ.\n", (const W_CHAR*)files[0],
              (const W_CHAR*)files[1]);
-    return_code = -3;
+    return_code = 1;
   } else {
     WPRINTF("\nFiles %s and %s are identical.\n", (const W_CHAR*)files[0],
             (const W_CHAR*)files[1]);

examples/anim_dump.c

@@ -12,6 +12,7 @@
 // Author: Skal (pascal.massimino@gmail.com)
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>  // for 'strcmp'.
 
 #include "./anim_util.h"
@@ -35,6 +36,7 @@ static void Help(void) {
   printf("  -version ............ print version number and exit\n");
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int error = 0;
   const W_CHAR* dump_folder = TO_W_CHAR(".");
@@ -47,7 +49,7 @@ int main(int argc, const char* argv[]) {
 
   if (argc < 2) {
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   for (c = 1; !error && c < argc; ++c) {
@@ -73,7 +75,7 @@ int main(int argc, const char* argv[]) {
       suffix = TO_W_CHAR("pam");
     } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-version")) {
       int dec_version, demux_version;
       GetAnimatedImageVersions(&dec_version, &demux_version);
@@ -82,7 +84,7 @@ int main(int argc, const char* argv[]) {
              (dec_version >> 0) & 0xff,
              (demux_version >> 16) & 0xff, (demux_version >> 8) & 0xff,
              (demux_version >> 0) & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {
       uint32_t i;
       AnimatedImage image;
@@ -121,5 +123,5 @@ int main(int argc, const char* argv[]) {
       ClearAnimatedImage(&image);
     }
   }
-  FREE_WARGV_AND_RETURN(error ? 1 : 0);
+  FREE_WARGV_AND_RETURN(error ? EXIT_FAILURE : EXIT_SUCCESS);
 }

examples/cwebp.c

@@ -651,8 +651,9 @@ static const char* const kErrorMessages[VP8_ENC_ERROR_LAST] = {
 
 //------------------------------------------------------------------------------
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
-  int return_value = -1;
+  int return_value = EXIT_FAILURE;
   const char* in_file = NULL, *out_file = NULL, *dump_file = NULL;
   FILE* out = NULL;
   int c;
@@ -686,22 +687,22 @@ int main(int argc, const char* argv[]) {
       !WebPPictureInit(&original_picture) ||
       !WebPConfigInit(&config)) {
     fprintf(stderr, "Error! Version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   if (argc == 1) {
     HelpShort();
-    FREE_WARGV_AND_RETURN(0);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   for (c = 1; c < argc; ++c) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       HelpShort();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-H") || !strcmp(argv[c], "-longhelp")) {
       HelpLong();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-o") && c + 1 < argc) {
       out_file = (const char*)GET_WARGV(argv, ++c);
     } else if (!strcmp(argv[c], "-d") && c + 1 < argc) {
@@ -842,7 +843,7 @@ int main(int argc, const char* argv[]) {
       printf("libsharpyuv: %d.%d.%d\n",
              (sharpyuv_version >> 24) & 0xff, (sharpyuv_version >> 16) & 0xffff,
              sharpyuv_version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-progress")) {
       show_progress = 1;
     } else if (!strcmp(argv[c], "-quiet")) {
@@ -904,7 +905,7 @@ int main(int argc, const char* argv[]) {
         if (i == kNumTokens) {
           fprintf(stderr, "Error! Unknown metadata type '%.*s'\n",
                   (int)(token - start), start);
-          FREE_WARGV_AND_RETURN(-1);
+          FREE_WARGV_AND_RETURN(EXIT_FAILURE);
         }
         start = token + 1;
       }
@@ -923,14 +924,14 @@ int main(int argc, const char* argv[]) {
     } else if (argv[c][0] == '-') {
       fprintf(stderr, "Error! Unknown option '%s'\n", argv[c]);
       HelpLong();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       in_file = (const char*)GET_WARGV(argv, c);
     }
 
     if (parse_error) {
       HelpLong();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
   if (in_file == NULL) {
@@ -1231,7 +1232,7 @@ int main(int argc, const char* argv[]) {
       PrintMetadataInfo(&metadata, metadata_written);
     }
   }
-  return_value = 0;
+  return_value = EXIT_SUCCESS;
 
  Error:
   WebPMemoryWriterClear(&memory_writer);

examples/dwebp.c

@@ -177,6 +177,7 @@ static uint8_t* AllocateExternalBuffer(WebPDecoderConfig* config,
   return external_buffer;
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int ok = 0;
   const char* in_file = NULL;
@@ -197,14 +198,14 @@ int main(int argc, const char* argv[]) {
 
   if (!WebPInitDecoderConfig(&config)) {
     fprintf(stderr, "Library version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   for (c = 1; c < argc; ++c) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
       out_file = (const char*)GET_WARGV(argv, ++c);
     } else if (!strcmp(argv[c], "-alpha")) {
@@ -227,7 +228,7 @@ int main(int argc, const char* argv[]) {
       const int version = WebPGetDecoderVersion();
       printf("%d.%d.%d\n",
              (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-pgm")) {
       format = PGM;
     } else if (!strcmp(argv[c], "-yuv")) {
@@ -293,21 +294,21 @@ int main(int argc, const char* argv[]) {
     } else if (argv[c][0] == '-') {
       fprintf(stderr, "Unknown option '%s'\n", argv[c]);
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       in_file = (const char*)GET_WARGV(argv, c);
     }
 
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
 
   if (in_file == NULL) {
     fprintf(stderr, "missing input file!!\n");
     Help();
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   if (quiet) verbose = 0;
@@ -316,7 +317,7 @@ int main(int argc, const char* argv[]) {
     VP8StatusCode status = VP8_STATUS_OK;
     size_t data_size = 0;
     if (!LoadWebP(in_file, &data, &data_size, bitstream)) {
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
 
     switch (format) {
@@ -415,7 +416,7 @@ int main(int argc, const char* argv[]) {
   WebPFreeDecBuffer(output_buffer);
   WebPFree((void*)external_buffer);
   WebPFree((void*)data);
-  FREE_WARGV_AND_RETURN(ok ? 0 : -1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 //------------------------------------------------------------------------------

examples/gif2webp.c

@@ -96,6 +96,7 @@ static void Help(void) {
 
 //------------------------------------------------------------------------------
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int verbose = 0;
   int gif_error = GIF_ERROR;
@@ -140,7 +141,7 @@ int main(int argc, const char* argv[]) {
       !WebPPictureInit(&frame) || !WebPPictureInit(&curr_canvas) ||
       !WebPPictureInit(&prev_canvas)) {
     fprintf(stderr, "Error! Version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
   config.lossless = 1;  // Use lossless compression by default.
 
@@ -150,14 +151,14 @@ int main(int argc, const char* argv[]) {
 
   if (argc == 1) {
     Help();
-    FREE_WARGV_AND_RETURN(0);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   for (c = 1; c < argc; ++c) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-o") && c < argc - 1) {
       out_file = GET_WARGV(argv, ++c);
     } else if (!strcmp(argv[c], "-lossy")) {
@@ -216,7 +217,7 @@ int main(int argc, const char* argv[]) {
           fprintf(stderr, "Error! Unknown metadata type '%.*s'\n",
                   (int)(token - start), start);
           Help();
-          FREE_WARGV_AND_RETURN(-1);
+          FREE_WARGV_AND_RETURN(EXIT_FAILURE);
         }
         start = token + 1;
       }
@@ -229,7 +230,7 @@ int main(int argc, const char* argv[]) {
              (enc_version >> 16) & 0xff, (enc_version >> 8) & 0xff,
              enc_version & 0xff, (mux_version >> 16) & 0xff,
              (mux_version >> 8) & 0xff, mux_version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-quiet")) {
       quiet = 1;
       enc_options.verbose = 0;
@@ -242,14 +243,14 @@ int main(int argc, const char* argv[]) {
     } else if (argv[c][0] == '-') {
       fprintf(stderr, "Error! Unknown option '%s'\n", argv[c]);
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       in_file = GET_WARGV(argv, c);
     }
 
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
 
@@ -593,7 +594,7 @@ int main(int argc, const char* argv[]) {
 #endif
   }
 
-  FREE_WARGV_AND_RETURN(!ok);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 #else  // !WEBP_HAVE_GIF
@@ -601,7 +602,7 @@ int main(int argc, const char* argv[]) {
 int main(int argc, const char* argv[]) {
   fprintf(stderr, "GIF support not enabled in %s.\n", argv[0]);
   (void)argc;
-  return 0;
+  return EXIT_FAILURE;
 }
 
 #endif

examples/img2webp.c

@@ -130,6 +130,7 @@ static int SetLoopCount(int loop_count, WebPData* const webp_data) {
 
 //------------------------------------------------------------------------------
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   const char* output = NULL;
   WebPAnimEncoder* enc = NULL;
@@ -151,7 +152,7 @@ int main(int argc, const char* argv[]) {
   INIT_WARGV(argc, argv);
 
   ok = ExUtilInitCommandLineArguments(argc - 1, argv + 1, &cmd_args);
-  if (!ok) FREE_WARGV_AND_RETURN(1);
+  if (!ok) FREE_WARGV_AND_RETURN(EXIT_FAILURE);
 
   argc = cmd_args.argc_;
   argv = cmd_args.argv_;
@@ -199,7 +200,7 @@ int main(int argc, const char* argv[]) {
         verbose = 1;
       } else if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
         Help();
-        FREE_WARGV_AND_RETURN(0);
+        FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
       } else if (!strcmp(argv[c], "-version")) {
         const int enc_version = WebPGetEncoderVersion();
         const int mux_version = WebPGetMuxVersion();
@@ -335,5 +336,5 @@ int main(int argc, const char* argv[]) {
   }
   WebPDataClear(&webp_data);
   ExUtilDeleteCommandLineArguments(&cmd_args);
-  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }

examples/vwebp.c

@@ -506,7 +506,7 @@ int main(int argc, char* argv[]) {
 
   if (!WebPInitDecoderConfig(config)) {
     fprintf(stderr, "Library version mismatch!\n");
-    FREE_WARGV_AND_RETURN(-1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
   config->options.dithering_strength = 50;
   config->options.alpha_dithering_strength = 100;
@@ -518,7 +518,7 @@ int main(int argc, char* argv[]) {
     int parse_error = 0;
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help")) {
       Help();
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-noicc")) {
       kParams.use_color_profile = 0;
     } else if (!strcmp(argv[c], "-nofancy")) {
@@ -541,7 +541,7 @@ int main(int argc, char* argv[]) {
              (dec_version >> 16) & 0xff, (dec_version >> 8) & 0xff,
              dec_version & 0xff, (dmux_version >> 16) & 0xff,
              (dmux_version >> 8) & 0xff, dmux_version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-mt")) {
       config->options.use_threads = 1;
     } else if (!strcmp(argv[c], "--")) {
@@ -553,7 +553,7 @@ int main(int argc, char* argv[]) {
     } else if (argv[c][0] == '-') {
       printf("Unknown option '%s'\n", argv[c]);
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     } else {
       kParams.file_name = (const char*)GET_WARGV(argv, c);
       file_name_argv_index = c;
@@ -561,14 +561,14 @@ int main(int argc, char* argv[]) {
 
     if (parse_error) {
       Help();
-      FREE_WARGV_AND_RETURN(-1);
+      FREE_WARGV_AND_RETURN(EXIT_FAILURE);
     }
   }
 
   if (kParams.file_name == NULL) {
     printf("missing input file!!\n");
     Help();
-    FREE_WARGV_AND_RETURN(0);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   if (!ImgIoUtilReadFile(kParams.file_name,
@@ -643,11 +643,11 @@ int main(int argc, char* argv[]) {
 
   // Should only be reached when using FREEGLUT:
   ClearParams();
-  FREE_WARGV_AND_RETURN(0);
+  FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
 
  Error:
   ClearParams();
-  FREE_WARGV_AND_RETURN(-1);
+  FREE_WARGV_AND_RETURN(EXIT_FAILURE);
 }
 
 #else   // !WEBP_HAVE_GL
@@ -655,7 +655,7 @@ int main(int argc, char* argv[]) {
 int main(int argc, const char* argv[]) {
   fprintf(stderr, "OpenGL support not enabled in %s.\n", argv[0]);
   (void)argc;
-  return 0;
+  return EXIT_FAILURE;
 }
 
 #endif

examples/webpinfo.c

@@ -14,6 +14,7 @@
 
 #include <assert.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifdef HAVE_CONFIG_H
 #include "webp/config.h"
@@ -1120,6 +1121,7 @@ static void Help(void) {
          "  -bitstream_info .... Parse bitstream header.\n");
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int c, quiet = 0, show_diag = 0, show_summary = 0;
   int parse_bitstream = 0;
@@ -1130,7 +1132,7 @@ int main(int argc, const char* argv[]) {
 
   if (argc == 1) {
     Help();
-    FREE_WARGV_AND_RETURN(WEBP_INFO_OK);
+    FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
   }
 
   // Parse command-line input.
@@ -1138,7 +1140,7 @@ int main(int argc, const char* argv[]) {
     if (!strcmp(argv[c], "-h") || !strcmp(argv[c], "-help") ||
         !strcmp(argv[c], "-H") || !strcmp(argv[c], "-longhelp")) {
       Help();
-      FREE_WARGV_AND_RETURN(WEBP_INFO_OK);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else if (!strcmp(argv[c], "-quiet")) {
       quiet = 1;
     } else if (!strcmp(argv[c], "-diag")) {
@@ -1151,7 +1153,7 @@ int main(int argc, const char* argv[]) {
       const int version = WebPGetDecoderVersion();
       printf("WebP Decoder version: %d.%d.%d\n",
              (version >> 16) & 0xff, (version >> 8) & 0xff, version & 0xff);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {  // Assume the remaining are all input files.
       break;
     }
@@ -1159,7 +1161,7 @@ int main(int argc, const char* argv[]) {
 
   if (c == argc) {
     Help();
-    FREE_WARGV_AND_RETURN(WEBP_INFO_INVALID_COMMAND);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   // Process input files one by one.
@@ -1182,5 +1184,6 @@ int main(int argc, const char* argv[]) {
     webp_info_status = AnalyzeWebP(&webp_info, &webp_data);
     WebPDataClear(&webp_data);
   }
-  FREE_WARGV_AND_RETURN(webp_info_status);
+  FREE_WARGV_AND_RETURN((webp_info_status == WEBP_INFO_OK) ? EXIT_SUCCESS
+                                                           : EXIT_FAILURE);
 }

examples/webpmux.c

@@ -59,6 +59,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+
 #include "webp/decode.h"
 #include "webp/mux.h"
 #include "../examples/example_util.h"
@@ -1225,6 +1226,7 @@ static int Process(const Config* config) {
 //------------------------------------------------------------------------------
 // Main.
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   Config config;
   int ok;
@@ -1238,7 +1240,7 @@ int main(int argc, const char* argv[]) {
     PrintHelp();
   }
   DeleteConfig(&config);
-  FREE_WARGV_AND_RETURN(!ok);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 //------------------------------------------------------------------------------

extras/get_disto.c

@@ -227,10 +227,11 @@ static void Help(void) {
           WebPGetEnabledInputFileFormats());
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   WebPPicture pic1, pic2;
   size_t size1 = 0, size2 = 0;
-  int ret = 1;
+  int ret = EXIT_FAILURE;
   float disto[5];
   int type = 0;
   int c;
@@ -246,7 +247,7 @@ int main(int argc, const char* argv[]) {
 
   if (!WebPPictureInit(&pic1) || !WebPPictureInit(&pic2)) {
     fprintf(stderr, "Can't init pictures\n");
-    FREE_WARGV_AND_RETURN(1);
+    FREE_WARGV_AND_RETURN(EXIT_FAILURE);
   }
 
   for (c = 1; c < argc; ++c) {
@@ -262,7 +263,7 @@ int main(int argc, const char* argv[]) {
       use_gray = 1;
     } else if (!strcmp(argv[c], "-h")) {
       help = 1;
-      ret = 0;
+      ret = EXIT_SUCCESS;
     } else if (!strcmp(argv[c], "-o")) {
       if (++c == argc) {
         fprintf(stderr, "missing file name after %s option.\n", argv[c - 1]);
@@ -337,7 +338,8 @@ int main(int argc, const char* argv[]) {
       fprintf(stderr, "Error during lossless encoding.\n");
       goto End;
     }
-    ret = ImgIoUtilWriteFile(output, data, data_size) ? 0 : 1;
+    ret = ImgIoUtilWriteFile(output, data, data_size) ? EXIT_SUCCESS
+                                                      : EXIT_FAILURE;
     WebPFree(data);
     if (ret) goto End;
 #else
@@ -345,9 +347,10 @@ int main(int argc, const char* argv[]) {
     (void)data_size;
     fprintf(stderr, "Cannot save the difference map. Please recompile "
                     "without the WEBP_REDUCE_CSP flag.\n");
+    goto End;
 #endif  // WEBP_REDUCE_CSP
   }
-  ret = 0;
+  ret = EXIT_SUCCESS;
 
  End:
   WebPPictureFree(&pic1);

extras/vwebp_sdl.c

@@ -15,6 +15,7 @@
 // Author: James Zern (jzern@google.com)
 
 #include <stdio.h>
+#include <stdlib.h>
 
 #ifdef HAVE_CONFIG_H
 #include "webp/config.h"
@@ -49,6 +50,7 @@ static void ProcessEvents(void) {
   }
 }
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, char* argv[]) {
   int c;
   int ok = 0;
@@ -61,7 +63,7 @@ int main(int argc, char* argv[]) {
     size_t webp_size = 0;
     if (!strcmp(argv[c], "-h")) {
       printf("Usage: %s [-h] image.webp [more_files.webp...]\n", argv[0]);
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {
       file = (const char*)GET_WARGV(argv, c);
     }
@@ -87,7 +89,7 @@ int main(int argc, char* argv[]) {
 
  Error:
   SDL_Quit();
-  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }
 
 #else  // !WEBP_HAVE_SDL

extras/webp_quality.c

@@ -15,6 +15,7 @@
 #include "imageio/imageio_util.h"
 #include "../examples/unicode.h"
 
+// Returns EXIT_SUCCESS on success, EXIT_FAILURE on failure.
 int main(int argc, const char* argv[]) {
   int c;
   int quiet = 0;
@@ -27,7 +28,7 @@ int main(int argc, const char* argv[]) {
       quiet = 1;
     } else if (!strcmp(argv[c], "-help") || !strcmp(argv[c], "-h")) {
       printf("webp_quality [-h][-quiet] webp_files...\n");
-      FREE_WARGV_AND_RETURN(0);
+      FREE_WARGV_AND_RETURN(EXIT_SUCCESS);
     } else {
       const char* const filename = (const char*)GET_WARGV(argv, c);
       const uint8_t* data = NULL;
@@ -50,5 +51,5 @@ int main(int argc, const char* argv[]) {
       free((void*)data);
     }
   }
-  FREE_WARGV_AND_RETURN(ok ? 0 : 1);
+  FREE_WARGV_AND_RETURN(ok ? EXIT_SUCCESS : EXIT_FAILURE);
 }

man/cwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH CWEBP 1 "March 26, 2024"
+.TH CWEBP 1 "April 30, 2024"
 .SH NAME
 cwebp \- compress an image file to a WebP file
 .SH SYNOPSIS
@@ -299,6 +299,13 @@ Note: each input format may not support all combinations.
 .B \-noasm
 Disable all assembly optimizations.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBcwebp\fP exits with the value of
+the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBcwebp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH BUGS
 Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp

man/dwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH DWEBP 1 "November 17, 2021"
+.TH DWEBP 1 "April 30, 2024"
 .SH NAME
 dwebp \- decompress a WebP file to an image file
 .SH SYNOPSIS
@@ -108,6 +108,13 @@ Print extra information (decoding time in particular).
 .B \-noasm
 Disable all assembly optimizations.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBdwebp\fP exits with the value of
+the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBdwebp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH BUGS
 Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp

man/gif2webp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH GIF2WEBP 1 "November 17, 2021"
+.TH GIF2WEBP 1 "April 30, 2024"
 .SH NAME
 gif2webp \- Convert a GIF image to WebP
 .SH SYNOPSIS
@@ -126,6 +126,13 @@ Print extra information.
 .B \-quiet
 Do not print anything.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBgif2webp\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBgif2webp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH BUGS
 Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp

man/img2webp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH IMG2WEBP 1 "March 17, 2023"
+.TH IMG2WEBP 1 "April 30, 2024"
 .SH NAME
 img2webp \- create animated WebP file from a sequence of input images.
 .SH SYNOPSIS
@@ -89,6 +89,13 @@ Specify the compression method to use. This parameter controls the
 trade off between encoding speed and the compressed file size and quality.
 Possible values range from 0 to 6. Default value is 4.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBimg2webp\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBimg2webp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH EXAMPLE
 img2webp -loop 2 in0.png -lossy in1.jpg -d 80 in2.tiff -o out.webp
 .br

man/vwebp.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH VWEBP 1 "November 17, 2021"
+.TH VWEBP 1 "April 30, 2024"
 .SH NAME
 vwebp \- decompress a WebP file and display it in a window
 .SH SYNOPSIS
@@ -72,6 +72,13 @@ Disable blending and disposal process, for debugging purposes.
 .B 'q' / 'Q' / ESC
 Quit.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBvwebp\fP exits with the value of
+the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBvwebp\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH BUGS
 Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp

man/webpinfo.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH WEBPINFO 1 "November 17, 2021"
+.TH WEBPINFO 1 "April 30, 2024"
 .SH NAME
 webpinfo \- print out the chunk level structure of WebP files
 along with basic integrity checks.
@@ -47,6 +47,13 @@ Detailed usage instructions.
 Input files in WebP format. Input files must come last, following
 options (if any). There can be multiple input files.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBwebpinfo\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBwebpinfo\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH BUGS
 Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp

man/webpmux.1

@@ -1,5 +1,5 @@
 .\"                                      Hey, EMACS: -*- nroff -*-
-.TH WEBPMUX 1 "November 17, 2021"
+.TH WEBPMUX 1 "April 30, 2024"
 .SH NAME
 webpmux \- create animated WebP files from non\-animated WebP images, extract
 frames from animated WebP images, and manage XMP/EXIF metadata and ICC profile.
@@ -186,6 +186,13 @@ Output file in WebP format.
 .TP
 The nature of EXIF, XMP and ICC data is not checked and is assumed to be valid.
 
+.SH EXIT STATUS
+If there were no problems during execution, \fBwebpmux\fP exits with the value
+of the C constant \fBEXIT_SUCCESS\fP. This is usually zero.
+.PP
+If an error occurs, \fBwebpmux\fP exits with the value of the C constant
+\fBEXIT_FAILURE\fP. This is usually one.
+
 .SH BUGS
 Please report all bugs to the issue tracker:
 https://bugs.chromium.org/p/webp