style + minor bug fixes

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 309 insertions, 242 deletions

diff --git a/src/scrotty.c b/src/scrotty.c
index 7a0e31b..8a45b24 100644
--- a/src/scrotty.c
+++ b/src/scrotty.c
@@ -74,69 +74,77 @@ static const char* inttable[] =
 
 
 /**
- * `argv[0]` from `main`
+ * `argv[0]` from `main`.
  */
-static const char* execname;
+static const char *execname;
 
 /**
  * Arguments for `convert`,
  * the output file should be printed into `convert_args[2]`.
  * `NULL` is `convert` shall not be used.
  */
-static char** convert_args = NULL;
+static char **convert_args = NULL;
 
 
 /**
  * Create an PNM-file that is sent to `convert` for convertion
- * to a compressed format, or directly to a file
+ * to a compressed format, or directly to a file.
  * 
- * @param   fbname  The framebuffer device
- * @param   width   The width of the image
- * @param   height  The height of the image
+ * @param   fbname  The framebuffer device.
+ * @param   width   The width of the image.
+ * @param   height  The height of the image.
  * @param   fd      The file descriptor connected to `convert`'s stdin
- * @return          Zero on success, -1 on error
+ * @return          Zero on success, -1 on error.
  */
-static int save_pnm(const char* fbpath, long width, long height, int fd)
+static int
+save_pnm (const char *fbpath, long width, long height, int fd)
 {
   char buf[PATH_MAX];
-  FILE* file;
-  int saved_errno, fbfd, r, g, b;
+  FILE *file = NULL;
+  int fbfd = 1;
+  int r, g, b;
   ssize_t got, off;
+  uint32_t *pixel;
+  int saved_errno;
   
   /* Open the framebuffer device for reading. */
-  if (fbfd = open(fbpath, O_RDONLY), fbfd < 0)
-    return -1;
+  fbfd = open (fbpath, O_RDONLY);
+  if (fbfd == -1)
+    goto fail;
   
   /* Create a FILE*, for writing, for the image file. */
-  file = fdopen(fd, "w");
+  file = fdopen (fd, "w");
   if (file == NULL)
-    return saved_errno = errno, close(fbfd), errno = saved_errno, -1;
+    goto fail;
   
   /* The PNM image should begin with `P3\n%{width} %{height}\n%{colour max=255}\n`.
      ('\n' and ' ' can be exchanged at will.) */
-  fprintf(file, "P3\n%li %li\n255\n", width, height);
+  if (fprintf (file, "P3\n%li %li\n255\n", width, height) < 0)
+    goto fail;
   
   /* Convert raw framebuffer data into an PNM image. */
   for (off = 0;;)
     {
       /* Read data from the framebuffer, we may have up to 3 bytes buffered. */
-      got = read(fbfd, buf + off, sizeof(buf) - (size_t)off * sizeof(char));
+      got = read (fbfd, buf + off, sizeof (buf) - (size_t)off * sizeof (char));
       if (got < 0)
-	return saved_errno = errno, fclose(file), close(fbfd), errno = saved_errno, -1;
-      if (got += off, got == 0)
+	goto fail;
+      if (got == 0)
 	break;
+      got += off;
       
       /* Convert read pixels. */
       for (off = 0; off < got; off += 4)
 	{
 	  /* A pixel in the framebuffer is formatted as `%{blue}%{green}%{red}%{x}`
 	     in big-endian binary, or `%{x}%{red}%{green}%{blue}` in little-endian binary. */
-	  uint32_t* pixel = (uint32_t*)(buf + off);
+	  pixel = (uint32_t *)(buf + off);
 	  r = (*pixel >> 16) & 255;
 	  g = (*pixel >> 8) & 255;
 	  b = (*pixel >> 0) & 255;
 	  /* A pixel in the PNM image is formatted as `%{red} %{green} %{blue} ` in text. */
-	  fprintf(file, "%s%s%s", inttable[r], inttable[g], inttable[b]);
+	  if (fprintf (file, "%s%s%s", inttable[r], inttable[g], inttable[b]) < 0)
+	    goto fail;
 	}
       
       /* If we read a whole number of pixels, reset the buffer, otherwise,
@@ -144,7 +152,7 @@ static int save_pnm(const char* fbpath, long width, long height, int fd)
       if (off != got)
 	{
 	  off -= 4;
-	  memcpy(buf, buf + off, (size_t)(got - off) * sizeof(char));
+	  memcpy (buf, buf + off, (size_t)(got - off) * sizeof (char));
 	  off = got - off;
 	}
       else
@@ -152,74 +160,89 @@ static int save_pnm(const char* fbpath, long width, long height, int fd)
     }
   
   /* Close files and return successfully. */
-  fflush(file);
-  fclose(file);
-  close(fbfd);
+  fflush (file);
+  fclose (file);
+  close (fbfd);
   return 0;
+  
+ fail:
+  saved_errno = errno;
+  if (file != NULL)
+    fclose (file);
+  if (fbfd >= 0)
+    close (fbfd);
+  errno = saved_errno;
+  return -1;
 }
 
 
 /**
- * Create an image of a framebuffer
+ * Create an image of a framebuffer.
  * 
- * @param   fbname    The framebuffer device
- * @param   imgname   The pathname of the output image
- * @param   width     The width of the image
- * @param   height    The height of the image
- * @return            Zero on success, -1 on error
+ * @param   fbname    The framebuffer device.
+ * @param   imgname   The pathname of the output image.
+ * @param   width     The width of the image.
+ * @param   height    The height of the image.
+ * @return            Zero on success, -1 on error.
  */
-static int save(const char* fbpath, const char* imgpath, long width, long height)
+static int
+save (const char *fbpath, const char *imgpath, long width, long height)
 {
-  int pipe_rw[2];
-  pid_t pid, reaped;
-  int saved_errno, status, fd;
+  int pipe_rw[2] = { -1, -1 };
+  pid_t pid;
+  int status;
+  int fd = -1;
+  int saved_errno;
   
   if (convert_args == NULL)
     goto no_convert;
   
   /* Create a pipe that for sending data into the `convert` program. */
-  if (pipe(pipe_rw) < 0)
-    return -1;
+  if (pipe (pipe_rw) < 0)
+    goto fail;
   
   /* Fork the process, the child will exec. `convert`. */
-  if (pid = fork(), pid == -1)
-    return saved_errno = errno, close(pipe_rw[0]), close(pipe_rw[1]), errno = saved_errno, -1;
+  pid = fork ();
+  if (pid == -1)
+    goto fail;
   
   /* Child process: */
   if (pid == 0)
     {
       /* Close the write-end of the pipe. */
-      close(pipe_rw[1]);
+      close (pipe_rw[1]);
       /* Turn the read-end of the into stdin. */
       if (pipe_rw[0] != STDIN_FILENO)
 	{
-	  close(STDIN_FILENO);
-	  dup2(pipe_rw[0], STDIN_FILENO);
-	  close(pipe_rw[0]);
+	  close (STDIN_FILENO);
+	  if (dup2 (pipe_rw[0], STDIN_FILENO) == -1)
+	    goto child_fail;
+	  close (pipe_rw[0]);
 	}
       /* Exec. `convert` to convert the PNM-image we create to a compressed image. */
-      sprintf(convert_args[2], "%s", imgpath);
-      execvp("convert", convert_args);
+      sprintf (convert_args[2], "%s", imgpath);
+      execvp ("convert", convert_args);
+      
+    child_fail:
       perror(execname);
-      exit(1);
+      _exit(1);
     }
   
   /* Parent process: */
   
   /* Close the read-end of the pipe. */
-  close(pipe_rw[0]);
+  close (pipe_rw[0]), pipe_rw[0] = -1;
   
   /* Create a PNM-image of the framebuffer. */
-  if (save_pnm(fbpath, width, height, pipe_rw[1]) < 0)
-    return saved_errno = errno, close(pipe_rw[1]), errno = saved_errno, -1;
+  if (save_pnm (fbpath, width, height, pipe_rw[1]) < 0)
+    goto fail;
   
   /* Close the write-end of the pipe. */
-  close(pipe_rw[1]);
+  close (pipe_rw[1]), pipe_rw[1] = -1;
   
   /* Wait for `convert` to exit. */
-  for (reaped = 0; reaped != pid;)
-    if (reaped = waitpid(pid, &status, 0), reaped < 0)
-      return -1;
+  if (waitpid (pid, &status, 0) < 0)
+    goto fail;
   
   /* Return successfully if and only if `convert` did. */
   return status == 0 ? 0 : -1;
@@ -229,65 +252,88 @@ static int save(const char* fbpath, const char* imgpath, long width, long height
   
  no_convert:
   /* Open output file. */
-  if (fd = open(imgpath, O_WRONLY | O_CREAT | O_TRUNC,
-		S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH), fd == -1)
-    return -1;
+  if (fd = open (imgpath, O_WRONLY | O_CREAT | O_TRUNC,
+		 S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH), fd == -1)
+    goto fail;
   
   /* Save image. */
-  if (save_pnm(fbpath, width, height, fd) < 0)
-    return saved_errno = errno, close(fd), errno = saved_errno, -1;
+  if (save_pnm (fbpath, width, height, fd) < 0)
+    goto fail;
   
-  close(fd);
+  close (fd);
   return 0;
+  
+ fail:
+  saved_errno = errno;
+  if (pipe_rw[0] >= 0)
+    close (pipe_rw[0]);
+  if (pipe_rw[1] >= 0)
+    close (pipe_rw[1]);
+  if (fd >= 0)
+    close (fd);
+  errno = saved_errno;
+  return -1;
 }
 
 
 /**
- * Get the dimensions of the framebuffer
+ * Get the dimensions of the framebuffer.
  * 
- * @param   fbno    The number of the framebuffer
- * @param   width   Output parameter for the width of the image
- * @param   height  Output parameter for the height of the image
- * @return          Zero on success, -1 on error
+ * @param   fbno    The number of the framebuffer.
+ * @param   width   Output parameter for the width of the image.
+ * @param   height  Output parameter for the height of the image.
+ * @return          Zero on success, -1 on error.
  */
-static int measure(int fbno, long* width, long* height)
+static int
+measure (int fbno, long *width, long *height)
 {
   char buf[PATH_MAX];
-  char* delim;
-  int sizefd, saved_errno;
+  char *delim;
+  int sizefd = -1;
   ssize_t got;
+  int saved_errno;
   
   /* Open the file with the framebuffer's dimensions. */
-  sprintf(buf, SYSDIR "/class/graphics/fb%i/virtual_size", fbno);
-  if (sizefd = open(buf, O_RDONLY), sizefd < 0)
-    return -1;
+  sprintf (buf, SYSDIR "/class/graphics/fb%i/virtual_size", fbno);
+  sizefd = open (buf, O_RDONLY);
+  if (sizefd == -1)
+    goto fail;
   
   /* Get the dimensions of the framebuffer. */
-  if (got = read(sizefd, buf, sizeof(buf) / sizeof(char) - 1), got < 0)
-    return saved_errno = errno, close(sizefd), errno = saved_errno, -1;
-  close(sizefd);
+  got = read (sizefd, buf, sizeof (buf) / sizeof (char) - 1);
+  if (got < 0)
+    goto fail;
+  close (sizefd);
   
   /* The read content is formated as `%{width},%{height}\n`,
      convert it to `%{width}\0%{height}\0` and parse it. */
   buf[got] = '\0';
-  delim = strchr(buf, ',');
+  delim = strchr (buf, ',');
   *delim++ = '\0';
-  *width = atol(buf);
-  *height = atol(delim);
+  *width = atol (buf);
+  *height = atol (delim);
   
   return 0;
+  
+ fail:
+  saved_errno = errno;
+  if (sizefd >= 0)
+    close (sizefd);
+  errno = saved_errno;
+  return -1;
 }
 
 
 /**
- * Duplicate all '%':s in a buffer until the first occurrence of a zero byte
+ * Duplicate all '%':s in a buffer until the first occurrence of a zero byte.
  * 
- * @param   buf  The buffer
- * @param   n    The size of the buffer
- * @return       -1 if the buffer is too small, otherwise
- *               the new position of the first zero byte
+ * @param   buf  The buffer.
+ * @param   n    The size of the buffer.
+ * @return       -1 if the buffer is too small, otherwise.
+ *               the new position of the first zero byte.
  */
-static ssize_t duplicate_percents(char* restrict buf, size_t n)
+static ssize_t
+duplicate_percents (char *restrict buf, size_t n)
 {
   size_t p = 0, pi, pc = 0, i;
   
@@ -303,8 +349,8 @@ static ssize_t duplicate_percents(char* restrict buf, size_t n)
   /* Duplicate all '%':s. */
   for (pi = 0; pi < pc; pi++)
     {
-      p = (size_t)(strchr(buf + p, '%') - buf);
-      memmove(buf + p + 1, buf + p, (i - (p - pi)) * sizeof(char));
+      p = (size_t)(strchr (buf + p, '%') - buf);
+      memmove (buf + p + 1, buf + p, (i - (p - pi)) * sizeof (char));
       p += 2;
     }
   
@@ -313,24 +359,24 @@ static ssize_t duplicate_percents(char* restrict buf, size_t n)
 
 
 /**
- * Parse and evaluate a --exec argument or filename pattern
+ * Parse and evaluate a --exec argument or filename pattern.
  * 
  * If `path != NULL` than all non-escaped spaces in
  * `pattern` will be stored as 255-bytes in `buf`.
  * 
- * @param   buf      The output buffer
- * @param   n        The size of `buf`
- * @param   pattern  The pattern to evaluate
- * @param   fbno     The index of the framebuffer
- * @param   width    The width of the image/framebuffer
- * @param   height   The height of the image/framebuffer
- * @param   path     The filename of the saved image, `NULL` during the evaluation of the filename pattern
- * @return           Zero on success, -1 on error
+ * @param   buf      The output buffer.
+ * @param   n        The size of `buf`.
+ * @param   pattern  The pattern to evaluate.
+ * @param   fbno     The index of the framebuffer.
+ * @param   width    The width of the image/framebuffer.
+ * @param   height   The height of the image/framebuffer.
+ * @param   path     The filename of the saved image, `NULL` during the evaluation of the filename pattern.
+ * @return           Zero on success, -1 on error.
  */
-static int evaluate(char* restrict buf, size_t n, const char* restrict pattern,
-		    int fbno, long width, long height, const char* restrict path)
+static int evaluate (char *restrict buf, size_t n, const char *restrict pattern,
+		     int fbno, long width, long height, const char *restrict path)
 {
-#define p(format, value)  r = snprintf(buf + i, n - i, format "%zn", value, &j)
+#define P(format, value)  r = snprintf (buf + i, n - i, format "%zn", value, &j)
   
   size_t i = 0;
   ssize_t j = 0;
@@ -349,20 +395,20 @@ static int evaluate(char* restrict buf, size_t n, const char* restrict pattern,
 	  if (path == NULL)
 	    if ((c == 'f') || (c == 'n'))
 	      continue;
-	  if      (c == 'i')  p("%i", fbno);
-	  else if (c == 'f')  p("%s", path);
-	  else if (c == 'n')  p("%s", strrchr(path, '/') ? (strrchr(path, '/') + 1) : path);
-	  else if (c == 'p')  p("%ju", (uintmax_t)width * (uintmax_t)height);
-	  else if (c == 'w')  p("%li", width);
-	  else if (c == 'h')  p("%li", height);
+	  if      (c == 'i')  P ("%i", fbno);
+	  else if (c == 'f')  P ("%s", path);
+	  else if (c == 'n')  P ("%s", strrchr (path, '/') ? (strrchr (path, '/') + 1) : path);
+	  else if (c == 'p')  P ("%ju", (uintmax_t)width * (uintmax_t)height);
+	  else if (c == 'w')  P ("%li", width);
+	  else if (c == 'h')  P ("%li", height);
 	  else if (c == '$')  r = 0, j = 1, buf[i] = '$';
 	  else
 	    continue;
 	  if ((r < 0) || (j <= 0))
 	    return -1;
 	  if ((c == 'f') || (c == 'n'))
-	    if (j = duplicate_percents(buf + i, n - i), j < 0)
-	      return errno = ENAMETOOLONG, -1;
+	    if (j = duplicate_percents (buf + i, n - i), j < 0)
+	      goto enametoolong;
 	  i += (size_t)j;
 	}
       else if (backslash)  buf[i++] = (c == 'n' ? '\n' : c), backslash = 0;
@@ -374,30 +420,37 @@ static int evaluate(char* restrict buf, size_t n, const char* restrict pattern,
       else                 buf[i++] = c;
       
       if (i >= n)
-	return errno = ENAMETOOLONG, -1;
+	goto enametoolong;
     }
   buf[i] = '\0';
   
   /* Check whether there are any '%' to expand. */
-  if (strchr(buf, '%') == NULL)
+  if (strchr (buf, '%') == NULL)
     return 0;
   
   /* Copy the buffer so we can reuse the buffer and use its old content for the format. */
-  fmt = alloca((strlen(buf) + 1) * sizeof(char));
-  memcpy(fmt, buf, (strlen(buf) + 1) * sizeof(char));
+  fmt = alloca ((strlen (buf) + 1) * sizeof (char));
+  memcpy (fmt, buf, (strlen (buf) + 1) * sizeof (char));
   
   /* Expand '%'. */
-  t = time(NULL);
-  localtime_r(&t, &tm);
+  t = time (NULL);
+  localtime_r (&t, &tm);
+#ifdef __GNUC__
 # pragma GCC diagnostic push
 # pragma GCC diagnostic ignored "-Wformat-nonliteral"
-  if (strftime(buf, n, fmt, &tm) == 0)
+#endif
+  if (strftime (buf, n, fmt, &tm) == 0)
+    goto enametoolong; /* No errors are defined for `strftime`. */
+#ifdef __GNUC__
 # pragma GCC diagnostic pop
-    return errno = ENAMETOOLONG, -1;
+#endif
   
   return 0;
   
-#undef p
+ enametoolong:
+  return errno = ENAMETOOLONG, -1;
+  
+#undef P
 }
 
 
@@ -407,12 +460,13 @@ static int evaluate(char* restrict buf, size_t n, const char* restrict pattern,
  * @param   flatten_args  The arguments to run, 255 delimits the arguments
  * @return                Zero on success -1 on error
  */
-static int exec_image(char* flatten_args)
+static int
+exec_image (char *flatten_args)
 {
-  char** args;
-  char* arg;
+  char **args;
+  char *arg;
   size_t i, arg_count = 1;
-  pid_t pid, reaped;
+  pid_t pid;
   int status;
   
   /* Count arguments. */
@@ -421,39 +475,37 @@ static int exec_image(char* flatten_args)
       arg_count++;
   
   /* Allocate argument array. */
-  args = alloca((arg_count + 1) * sizeof(char*));
+  args = alloca ((arg_count + 1) * sizeof (char*));
   
   /* Unflatten argument array. */
   for (arg = flatten_args, i = 0;;)
     {
       args[i++] = arg;
-      arg = strchr(arg, 255);
+      arg = strchr (arg, 255);
       if (arg == NULL)
 	break;
       *arg++ = '\0';
     }
   args[i] = NULL;
-
+  
   /* Fork process. */
-  pid = fork();
+  pid = fork ();
   if (pid == -1)
     return -1;
 
   /* Child process: */
   if (pid == 0)
     {
-      execvp(*args, args);
-      perror(execname);
-      exit(1);
-      return -1;
+      execvp (*args, args);
+      perror (execname);
+      _exit (1);
     }
   
   /* Parent process: */
   
   /* Wait for child to exit. */
-  for (reaped = 0; reaped != pid;)
-    if (reaped = waitpid(pid, &status, 0), reaped < 0)
-      return -1;
+  if (waitpid(pid, &status, 0) < 0)
+    return -1;
   
   /* Return successfully if and only if `the child` did. */
   return status == 0 ? 0 : -1;
@@ -461,54 +513,55 @@ static int exec_image(char* flatten_args)
 
 
 /**
- * Take a screenshot of a framebuffer
+ * Take a screenshot of a framebuffer.
  * 
- * @param   fbno         The number of the framebuffer
- * @param   raw          Save in PNM rather than in PNG?
- * @param   filepattern  The pattern for the filename, `NULL` for default
+ * @param   fbno         The number of the framebuffer.
+ * @param   raw          Save in PNM rather than in PNG?.
+ * @param   filepattern  The pattern for the filename, `NULL` for default.
  * @param   execpattern  The pattern for the command to run to
- *                       process the image, `NULL` for default
- * @return               Zero on success, -1 on error, 1 if the framebuffer does not exist
+ *                       process the image, `NULL` for default.
+ * @return               Zero on success, -1 on error, 1 if the framebuffer does not exist.
  */
-static int save_fb(int fbno, int raw, const char* filepattern, const char* execpattern)
+static int
+save_fb (int fbno, int raw, const char *filepattern, const char *execpattern)
 {
   char fbpath[PATH_MAX];
   char imgpath[PATH_MAX];
-  char* execargs = NULL;
-  char* old;
+  char *execargs = NULL;
+  void *new;
   long width, height;
   size_t size = PATH_MAX;
   int i, saved_errno;
   
   /* Get pathname for framebuffer, and stop if we have read all existing ones. */
-  sprintf(fbpath, DEVDIR "/fb%i", fbno);
-  if (access(fbpath, F_OK))
+  sprintf (fbpath, DEVDIR "/fb%i", fbno);
+  if (access (fbpath, F_OK))
     return 1;
   
   /* Get the size of the framebuffer. */
-  if (measure(fbno, &width, &height) < 0)
-    return -1;
+  if (measure (fbno, &width, &height) < 0)
+    goto fail;
 
   /* Get output pathname. */
   if (filepattern == NULL)
     {
-      sprintf(imgpath, "fb%i.%s", fbno, (raw ? "pnm" : "png"));
-      if (access(imgpath, F_OK) == 0)
+      sprintf (imgpath, "fb%i.%s", fbno, (raw ? "pnm" : "png"));
+      if (access (imgpath, F_OK) == 0)
 	for (i = 2;; i++)
 	  {
-	    sprintf(imgpath, "fb%i.%s.%i", fbno, (raw ? "pnm" : "png"), i);
-	    if (access(imgpath, F_OK))
+	    sprintf (imgpath, "fb%i.%s.%i", fbno, (raw ? "pnm" : "png"), i);
+	    if (access (imgpath, F_OK))
 	      break;
 	  }
     }
   else
-    if (evaluate(imgpath, (size_t)PATH_MAX, filepattern, fbno, width, height, NULL) < 0)
+    if (evaluate (imgpath, (size_t)PATH_MAX, filepattern, fbno, width, height, NULL) < 0)
       return -1;
   
   /* Take a screenshot of the current framebuffer. */
-  if (save(fbpath, imgpath, width, height) < 0)
-    return -1;
-  fprintf(stderr, "Saved framebuffer %i to %s\n", fbno, imgpath);
+  if (save (fbpath, imgpath, width, height) < 0)
+    goto fail;
+  fprintf (stderr, "Saved framebuffer %i to %s\n", fbno, imgpath);
   
   /* Should we run a command over the image? */
   if (execpattern == NULL)
@@ -516,82 +569,87 @@ static int save_fb(int fbno, int raw, const char* filepattern, const char* execp
   
   /* Get execute arguments. */
  retry:
-  execargs = realloc(old = execargs, size * sizeof(char));
+  new = realloc (execargs, size * sizeof (char));
   if (execargs == NULL)
-    return saved_errno = errno, free(old), errno = saved_errno, -1;
-  if (evaluate(execargs, size, execpattern, fbno, width, height, imgpath) < 0)
+    goto fail;
+  execargs = new;
+  if (evaluate (execargs, size, execpattern, fbno, width, height, imgpath) < 0)
     {
       if ((errno != ENAMETOOLONG) || ((size >> 8) <= PATH_MAX))
-	return -1;
+	goto fail;
       size <<= 1;
       goto retry;
     }
   
   /* Run command over image. */
-  i = exec_image(execargs);
+  if (exec_image (execargs) < 0)
+    goto fail;
+  free (execargs);
+  return 0;
+  
+ fail:
   saved_errno = errno;
-  free(execargs);
-  return errno = saved_errno, i;
+  free (execargs);
+  errno = saved_errno;
+  return -1;
 }
 
 
-#define p(...)  if (printf(__VA_ARGS__) < 0)  return -1;
-
-
 /**
- * Print usage information
+ * Print usage information.
  * 
- * @return  Zero on success, -1 on error
+ * @return  Zero on success, -1 on error.
  */
-static int print_help(void)
+static int
+print_help(void)
 {
-  p("SYNOPSIS\n");
-  p("\t%s [options...] [filename-pattern] [-- options-for-convert...]\n", execname);
-  p("\n");
-  p("OPTIONS\n");
-  p("\t--help         Print usage information.\n");
-  p("\t--version      Print program name and version.\n");
-  p("\t--copyright    Print copyright information.\n");
-  p("\t--raw          Save in PNM rather than in PNG.\n");
-  p("\t--exec CMD     Command to run for each saved image.\n");
-  p("\n");
-  p("SPECIAL STRINGS\n");
-  p("\tBoth the --exec and filename-pattern parameters can take format specifiers\n");
-  p("\tthat are expanded by scrotty when encountered. There are two types of format\n");
-  p("\tspecifier. Characters preceded by a '%%' are interpretted by strftime(3).\n");
-  p("\tSee `man strftime` for examples. These options may be used to refer to the\n");
-  p("\tcurrent date and time. The second kind are internal to scrotty and are prefixed\n");
-  p("\tby '$' or '\\'. The following specifiers are recognised:\n");
-  p("\n");
-  p("\t\n");
-  p("\t$i  framebuffer index\n");
-  p("\t$f  image filename/pathname (ignored when used in filename-pattern)\n");
-  p("\t$n  image filename          (ignored when used in filename-pattern)\n");
-  p("\t$p  image width multiplied by image height\n");
-  p("\t$w  image width\n");
-  p("\t$h  image height\n");
-  p("\t$$  expands to a literal '$'\n");
-  p("\t\\n  expands to a new line\n");
-  p("\t\\\\  expands to a literal '\\'\n");
-  p("\t\\   expands to a literal ' ' (the string is a backslash followed by a space)\n");
-  p("\n");
-  p("\tA space that is not prefixed by a backslash in --exec is interpreted as an\n");
-  p("\targument delimiter. This is the case even at the beginning and end of the\n");
-  p("\tstring and if a space was the previous character in the string.\n");
-  p("\n");
-  return 0;
+  return printf ("SYNOPSIS\n"
+		 "\t%s [options...] [filename-pattern] [-- options-for-convert...]\n"
+		 "\n"
+		 "OPTIONS\n"
+		 "\t--help         Print usage information.\n"
+		 "\t--version      Print program name and version.\n"
+		 "\t--copyright    Print copyright information.\n"
+		 "\t--raw          Save in PNM rather than in PNG.\n"
+		 "\t--exec CMD     Command to run for each saved image.\n"
+		 "\n"
+		 "SPECIAL STRINGS\n"
+		 "\tBoth the --exec and filename-pattern parameters can take format specifiers\n"
+		 "\tthat are expanded by scrotty when encountered. There are two types of format\n"
+		 "\tspecifier. Characters preceded by a '%%' are interpretted by strftime(3).\n"
+		 "\tSee `man strftime` for examples. These options may be used to refer to the\n"
+		 "\tcurrent date and time. The second kind are internal to scrotty and are prefixed\n"
+		 "\tby '$' or '\\'. The following specifiers are recognised:\n"
+		 "\n"
+		 "\t\n"
+		 "\t$i  framebuffer index\n"
+		 "\t$f  image filename/pathname (ignored when used in filename-pattern)\n"
+		 "\t$n  image filename          (ignored when used in filename-pattern)\n"
+		 "\t$p  image width multiplied by image height\n"
+		 "\t$w  image width\n"
+		 "\t$h  image height\n"
+		 "\t$$  expands to a literal '$'\n"
+		 "\t\\n  expands to a new line\n"
+		 "\t\\\\  expands to a literal '\\'\n"
+		 "\t\\   expands to a literal ' ' (the string is a backslash followed by a space)\n"
+		 "\n"
+		 "\tA space that is not prefixed by a backslash in --exec is interpreted as an\n"
+		 "\targument delimiter. This is the case even at the beginning and end of the\n"
+		 "\tstring and if a space was the previous character in the string.\n"
+		 "\n",
+		 execname) < 0 ? -1 : 0;
 }
 
 
 /**
- * Print program name and version
+ * Print program name and version.
  * 
- * @return  Zero on success, -1 on error
+ * @return  Zero on success, -1 on error.
  */
-static int print_version(void)
+static int
+print_version (void)
 {
-  p("%s %s\n", PROGRAM_NAME, PROGRAM_VERSION);
-  return 0;
+  return printf ("%s %s\n", PROGRAM_NAME, PROGRAM_VERSION) < 0 ? -1 : 0;
 }
 
 
@@ -600,30 +658,28 @@ static int print_version(void)
  * 
  * @return  Zero on success, -1 on error
  */
-static int print_copyright(void)
+static int
+print_copyright (void)
 {
-  p("scrotty -- Screenshot program for Linux's TTY\n");
-  p("Copyright (C) 2014, 2015  Mattias Andrée (maandree@member.fsf.org)\n");
-  p("\n");
-  p("This program is free software: you can redistribute it and/or modify\n");
-  p("it under the terms of the GNU General Public License as published by\n");
-  p("the Free Software Foundation, either version 3 of the License, or\n");
-  p("(at your option) any later version.\n");
-  p("\n");
-  p("This program is distributed in the hope that it will be useful,\n");
-  p("but WITHOUT ANY WARRANTY; without even the implied warranty of\n");
-  p("MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n");
-  p("GNU General Public License for more details.\n");
-  p("\n");
-  p("You should have received a copy of the GNU General Public License\n");
-  p("along with this program.  If not, see <http://www.gnu.org/licenses/>.\n");
-  return 0;
+  return printf ("scrotty -- Screenshot program for Linux's TTY\n"
+		 "Copyright (C) 2014, 2015  Mattias Andrée (maandree@member.fsf.org)\n"
+		 "\n"
+		 "This program is free software: you can redistribute it and/or modify\n"
+		 "it under the terms of the GNU General Public License as published by\n"
+		 "the Free Software Foundation, either version 3 of the License, or\n"
+		 "(at your option) any later version.\n"
+		 "\n"
+		 "This program is distributed in the hope that it will be useful,\n"
+		 "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
+		 "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
+		 "GNU General Public License for more details.\n"
+		 "\n"
+		 "You should have received a copy of the GNU General Public License\n"
+		 "along with this program.  If not, see <http://www.gnu.org/licenses/>.\n"
+		 ) < 0 ? -1 : 0;
 }
 
 
-#undef p
-
-
 /**
  * Take a screenshot of all framebuffers
  * 
@@ -631,48 +687,52 @@ static int print_copyright(void)
  * @param   argv  Command line arguments
  * @return        Zero on and only on success
  */
-int main(int argc, char* argv[])
+int main
+(int argc, char *argv[])
 {
+#define EXIT_USAGE(MSG)  \
+  return fprintf (stderr, "%s: %s. Type `%s --help` for help.\n", execname, MSG, execname), 1
+  
   int fbno, r, i, dash = argc, exec = -1, help = 0;
   int raw = 0, version = 0, copyright = 0, filepattern = -1;
   static char convert_args_0[] = "convert";
   static char convert_args_1[] = DEVDIR "/stdin";
   static char convert_args_2[PATH_MAX];
   
-  execname = *argv;
+  execname = argc ? *argv : "scrotty";
   
   /* Parse command line. */
   for (i = 1; i < argc; i++)
     {
-      if      (!strcmp(argv[i], "--help"))       help = 1;
-      else if (!strcmp(argv[i], "--version"))    version = 1;
-      else if (!strcmp(argv[i], "--copyright"))  copyright = 1;
-      else if (!strcmp(argv[i], "--raw"))        raw = 1;
-      else if (!strcmp(argv[i], "--exec"))       exec = ++i;
-      else if (!strcmp(argv[i], "--"))
+      if      (!strcmp (argv[i], "--help"))       help = 1;
+      else if (!strcmp (argv[i], "--version"))    version = 1;
+      else if (!strcmp (argv[i], "--copyright"))  copyright = 1;
+      else if (!strcmp (argv[i], "--raw"))        raw = 1;
+      else if (!strcmp (argv[i], "--exec"))       exec = ++i;
+      else if (!strcmp (argv[i], "--"))
 	{
 	  dash = i + 1;
 	  break;
 	}
       else if ((argv[i][0] == '-') || (filepattern != -1))
-	return fprintf(stderr, "Unrecognised option. Type `%s --help` for help.\n", execname), 1;
+	EXIT_USAGE ("Unrecognised option.");
       else
 	filepattern = i;
     }
   
   /* Check that --exec is valid. */
   if (exec == argc)
-    return fprintf(stderr, "--exec has no argument. Type `%s --help` for help.\n", execname), 1;
+    EXIT_USAGE ("--exec has no argument.");
   
-  /* Was --help, --version or --copyright used? */
-  if (help)       return -(print_help());
-  if (version)    return -(print_version());
-  if (copyright)  return -(print_copyright());
+  /* Was --help, --version, or --copyright used? */
+  if (help)       return -(print_help ());
+  if (version)    return -(print_version ());
+  if (copyright)  return -(print_copyright ());
   
   /* Create arguments for `convert`. */
   if ((!raw) || (dash < argc))
     {
-      convert_args = alloca((size_t)(4 + (argc - dash)) * sizeof(char*));
+      convert_args = alloca ((size_t)(4 + (argc - dash)) * sizeof (char*));
       convert_args[0] = convert_args_0;
       convert_args[1] = convert_args_1;
       convert_args[2] = convert_args_2;
@@ -684,13 +744,20 @@ int main(int argc, char* argv[])
   /* Take a screenshot of each framebuffer. */
   for (fbno = 0;; fbno++)
     {
-      r = save_fb(fbno, raw,
-		  (filepattern < 0 ? NULL : argv[filepattern]),
-		  (exec < 0 ? NULL : argv[exec]));
-      if (r < 0)  return perror(execname), 1;
-      if (r > 0)  break;
+      r = save_fb (fbno, raw,
+		   (filepattern < 0 ? NULL : argv[filepattern]),
+		   (exec < 0 ? NULL : argv[exec]));
+      if (r < 0)
+	goto fail;
+      if (r > 0)
+	break;
     }
   
   return 0;
+  
+ fail:
+  return perror (execname), 1;
+  
+#undef EXIT_USAGE
 }