Fix a POSIX violation for swab

1 files changed, 1 insertions, 1 deletions

diff --git a/include/unistd.h b/include/unistd.h
index a2b3105..a73279b 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -177,7 +177,7 @@ _FORTIFY_FN(swab) void swab(const void * _FORTIFY_POS0 __os,
         size_t __bs = __bos(__os, 0);
         size_t __bd = __bos(__od, 0);
 
-        if ((size_t)__n > __bs || (size_t)__n > __bd)
+        if (__n > 0 && ((size_t)__n > __bs || (size_t)__n > __bd))
                 __builtin_trap();
         return __orig_swab(__os, __od, __n);
 }