BUILD: mjson: Fix warning about unused variables

clang 15 reports unused variables in src/mjson.c:

  src/mjson.c:196:21: fatal error: expected ';' at end of declaration
    int __maybe_unused n = 0;

and

  src/mjson.c:727:17: fatal error: variable 'n' set but not used [-Wunused-but-set-variable]
    int sign = 1, n = 0;

An issue was created on the project, but it was not fixed for now:

   https://github.com/cesanta/mjson/issues/51

So for now, to fix the build issue, these variables are declared as unused.
Of course, if there is any update on this library, be careful to review this
patch first to be sure it is always required.

This patch should fix the issue #1868. It be backported as far as 2.4.

diff --git a/src/mjson.c b/src/mjson.c
index 549b0d5b8890f6c83701fa5bdd1fc6f5c1ab4f7f..73b7a5797f8fb8f4128d448f2841788253b8a473 100644 (file)
--- a/src/mjson.c
+++ b/src/mjson.c
@@ -192,7 +192,7 @@ static int plen1(const char *s) {
 }
 
 static int plen2(const char *s) {
-  int i = 0, n = 0;
+  int i = 0, __attribute__((unused)) n = 0;
   while (s[i] != '\0' && s[i] != '.' && s[i] != '[')
     n++, i += s[i] == '\\' ? 2 : 1;
   // printf("PLEN: s: [%s], [%.*s] => %d\n", s, i, s, n);
@@ -724,7 +724,7 @@ static int is_digit(int c) {
 /* NOTE: strtod() implementation by Yasuhiro Matsumoto. */
 static double mystrtod(const char *str, char **end) {
   double d = 0.0;
-  int sign = 1, n = 0;
+  int sign = 1, __attribute__((unused)) n = 0;
   const char *p = str, *a = str;
 
   /* decimal part */