json_parse demo: fix and use usage() function

diff --git a/apps/json_parse.c b/apps/json_parse.c
index c10026acea0d9f95b0db4b66cf36ad26a8922c39..59bf10abcfd0b087304d5381c6dcb45d85483940 100644 (file)
--- a/apps/json_parse.c
+++ b/apps/json_parse.c
@@ -31,7 +31,6 @@ static const char *fname = NULL;
 #define json_tokener_get_parse_end(tok) ((tok)->char_offset)
 #endif
 
-static void usage(int exitval, const char *errmsg);
 static void showmem(void);
 static int parseit(int fd, int (*callback)(struct json_object *));
 static int showobj(struct json_object *new_obj);
@@ -137,14 +136,15 @@ static int showobj(struct json_object *new_obj)
        return 0;
 }
 
-static void usage(int exitval, const char *errmsg)
+static void usage(const char *argv0, int exitval, const char *errmsg)
 {
        FILE *fp = stdout;
        if (exitval != 0)
                fp = stderr;
        if (errmsg != NULL)
                fprintf(fp, "ERROR: %s\n\n", errmsg);
-       fprintf(fp, "Usage: %s [-f] [-n] [-s]\n");
+
+       fprintf(fp, "Usage: %s [-f] [-n] [-s]\n", argv0);
        fprintf(fp, "  -f - Format the output with JSON_C_TO_STRING_PRETTY\n");
        fprintf(fp, "  -n - No output\n");
        fprintf(fp, "  -s - Parse in strict mode, flags:\n");
@@ -167,16 +167,15 @@ int main(int argc, char **argv)
                case 'f': formatted_output = 1; break;
                case 'n': show_output = 0; break;
                case 's': strict_mode = 1; break;
-               default: /* '?' */ fprintf(stderr, "Usage: %s [-f]\n", argv[0]); exit(EXIT_FAILURE);
+               default: /* '?' */ usage(argv[0], EXIT_FAILURE, NULL);
                }
        }
-
        if (optind >= argc)
        {
-               fprintf(stderr, "Expected argument after options\n");
-               exit(EXIT_FAILURE);
+               usage(argv[0], EXIT_FAILURE, "Expected argument after options");
        }
        fname = argv[optind];
+
        int fd = open(argv[optind], O_RDONLY, 0);
        showmem();
        if (parseit(fd, showobj) != 0)