util: introduce negative_errno()

[elogind.git] / src / shared / util.h

diff --git a/src/shared/util.h b/src/shared/util.h
index e405b02a8189760d4a9a773c160f330baba20bc7..af589b6708c79d04f7b917538a1c408935be3711 100644 (file)
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -794,6 +794,15 @@ static inline void _reset_errno_(int *saved_errno) {
 
 #define PROTECT_ERRNO _cleanup_(_reset_errno_) __attribute__((unused)) int _saved_errno_ = errno
 
+static inline int negative_errno(void) {
+        /* This helper should be used to shut up gcc if you know 'errno' is
+         * negative. Instead of "return -errno;", use "return negative_errno();"
+         * It will suppress bogus gcc warnings in case it assumes 'errno' might
+         * be 0 and thus the caller's error-handling might not be triggered. */
+        assert_return(errno > 0, -EINVAL);
+        return -errno;
+}
+
 struct _umask_struct_ {
         mode_t mask;
         bool quit;