Use exit codes consistently.

* doc/cflow.1: Document exit codes.
* doc/cflow.texi: Likewise.
* src/cflow.h: Define exit code constants.
* src/main.c: Use exit codes consistently.
* src/output.c: Likewise.
* src/parser.c: Likewise.
* src/posix.c: Likewise.
* src/rc.c: Likewise.

6 files changed, 47 insertions, 43 deletions

diff --git a/src/cflow.h b/src/cflow.h
index 28ba0db..e60d222 100644
--- a/src/cflow.h
+++ b/src/cflow.h
@@ -41,6 +41,12 @@
 # define setlocale(category, locale) /* empty */
 #endif
 
+/* Exit codes */
+#define EX_OK    0  /* Success */
+#define EX_FATAL 1  /* Fatal error */
+#define EX_SOFT  2  /* Some input files cannot be read or parsed */
+#define EX_USAGE 3  /* Command line usage error */
+
 #define NUMITEMS(a) sizeof(a)/sizeof((a)[0])
 
 struct linked_list_entry {
diff --git a/src/main.c b/src/main.c
index e78993a..4facaf5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -260,10 +260,9 @@ symbol_override(const char *str)
      Symbol *sp;
      
      ptr = strchr(str, ':');
-     if (!ptr) {
-          error(0, 0, _("%s: no symbol type supplied"), str);
-          return;
-     } else {
+     if (!ptr)
+          error(EX_USAGE, 0, _("%s: no symbol type supplied"), str);
+     else {
           name = strndup(str, ptr - str);
           if (ptr[1] == '=') {
                Symbol *alias = lookup(ptr+2);
@@ -281,10 +280,8 @@ symbol_override(const char *str)
                sp->flag = symbol_alias;
           } else {
                int type = find_option_type(symbol_optype, ptr+1, 0);
-               if (type == 0) {
-                    error(0, 0, _("unknown symbol type: %s"), ptr+1);
-                    return;
-               }
+               if (type == 0)
+                    error(EX_USAGE, 0, _("unknown symbol type: %s"), ptr+1);
                sp = install(name, INSTALL_OVERWRITE);
                sp->type = SymToken;
                sp->token_type = type;
@@ -310,7 +307,7 @@ set_print_option(char *str)
      
      opt = find_option_type(print_optype, str, 0);
      if (opt == 0) {
-          error(0, 0, _("unknown print option: %s"), str);
+          error(EX_USAGE, 0, _("unknown print option: %s"), str);
           return;
      }
      print_option |= opt;
@@ -432,19 +429,16 @@ parse_level_string(const char *str, char **return_ptr)
                c = p[-1];
                for (i = 1; i < num; i++) {
                     *p++ = c;
-                    if (*p == 0) {
-                         error(1, 0, _("level indent string is too long"));
-                         return;
-                    }
+                    if (*p == 0)
+                         error(EX_USAGE, 0,
+                               _("level indent string is too long"));
                }
                break;
           default:
           copy:
                *p++ = *str++;
-               if (*p == 0) {
-                    error(1, 0, _("level indent string is too long"));
-                    return;
-               }
+               if (*p == 0)
+                    error(EX_USAGE, 0, _("level indent string is too long"));
           }
      }
      *p = 0;
@@ -469,10 +463,8 @@ set_level_indent(const char *str)
      
      p = str;
      while (*p != '=') {
-          if (*p == 0) {
-               error(1, 0, _("level-indent syntax"));
-               return;
-          }
+          if (*p == 0)
+               error(EX_USAGE, 0, _("level-indent syntax"));
           p++;
      }
      ++p;
@@ -494,7 +486,7 @@ set_level_indent(const char *str)
           parse_level_string(p, &level_end[1]);
           break;
      default:
-          error(1, 0, _("unknown level indent option: %s"), str);
+          error(EX_USAGE, 0, _("unknown level indent option: %s"), str);
      }
 }
 
@@ -571,7 +563,7 @@ parse_opt (int key, char *arg, struct argp_state *state)
           break;
      case 'f':
           if (select_output_driver(arg))
-               argp_error(state, _("%s: No such output driver"), optarg);
+               error(EX_USAGE, 0, _("%s: No such output driver"), optarg);
           output_init();
           break;
      case OPT_LEVEL_INDENT:
@@ -599,7 +591,7 @@ parse_opt (int key, char *arg, struct argp_state *state)
                          SYMBOL_EXCLUDE(*arg);
                     break;
                default:
-                    argp_error(state, _("Unknown symbol class: %c"), *arg);
+                    error(EX_USAGE, 0, _("Unknown symbol class: %c"), *arg);
                }
           break;
      case OPT_OMIT_ARGUMENTS:
@@ -726,7 +718,7 @@ include_symbol(Symbol *sym)
 void
 xalloc_die(void)
 {
-     error(1, ENOMEM, _("Exiting"));
+     error(EX_FATAL, ENOMEM, _("Exiting"));
 }
 
 void
@@ -755,7 +747,8 @@ int
 main(int argc, char **argv)
 {
      int index;
-
+     int status = EX_OK;
+     
      set_program_name(argv[0]);
      argp_version_setup("cflow", program_authors);
      
@@ -769,14 +762,17 @@ main(int argc, char **argv)
      symbol_map = SM_FUNCTIONS|SM_STATIC|SM_UNDEFINED;
 
      if (getenv("POSIXLY_CORRECT")) {
-          if (select_output_driver("posix"))
-               error(1, 0, _("%s: No such output driver"), "posix");
+          if (select_output_driver("posix")) {
+               error(0, 0, _("INTERNAL ERROR: %s: No such output driver"),
+                     "posix");
+               abort();
+          }
           output_init();
      }
      
      sourcerc(&argc, &argv);
      if (argp_parse(&argp, argc, argv, ARGP_IN_ORDER, &index, NULL))
-          exit(1);
+          exit(EX_USAGE);
 
      if (print_option == 0)
           print_option = PRINT_TREE;
@@ -801,13 +797,15 @@ main(int argc, char **argv)
      while (argc--) {
           if (source(*argv++) == 0)
                yyparse();
+          else
+               status = EX_SOFT;
      }
 
      if (input_file_count == 0)
-             error(1, 0, _("no input files"));
+             error(EX_USAGE, 0, _("no input files"));
 
      output();
-     return 0;
+     return status;
 }
 
 
diff --git a/src/output.c b/src/output.c
index d46b496..2def906 100644
--- a/src/output.c
+++ b/src/output.c
@@ -419,7 +419,7 @@ output()
      } else {
           outfile = fopen(outname, "w");
           if (!outfile)
-               error(2, errno, _("cannot open file `%s'"), outname);
+               error(EX_FATAL, errno, _("cannot open file `%s'"), outname);
      } 
      
      set_level_mark(0, 0);
diff --git a/src/parser.c b/src/parser.c
index be82197..c26cd9c 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -307,8 +307,10 @@ nexttoken()
 int
 putback()
 {
-     if (curs == 0)
-          error(10, 0, _("INTERNAL ERROR: cannot return token to stream"));
+     if (curs == 0) {
+          error(0, 0, _("INTERNAL ERROR: cannot return token to stream"));
+          abort();
+     }
      curs--;
      if (curs > 0) {
           tok = token_stack[curs-1];
diff --git a/src/posix.c b/src/posix.c
index d0caac8..4a63183 100644
--- a/src/posix.c
+++ b/src/posix.c
@@ -55,7 +55,8 @@ posix_output_handler(cflow_output_command cmd,