handy.h: Generate compile error if macros called wrong

This extends the mechanism we added in 5.24 to more macros to make sure
that a macro is called with an integer and not a pointer.  It adds a

    "| 0"

to the macro parameter, which is illegal if the parameter is a pointer.

1 files changed, 4 insertions, 1 deletions

diff --git a/handy.h b/handy.h
index b1b50ff637..0f4b7f845c 100644
--- a/handy.h
+++ b/handy.h
@@ -910,7 +910,10 @@ patched there.  The file as of this writing is cpan/Devel-PPPort/parts/inc/misc
  * of operands.  Well, they are, but that is kind of the point.
  */
 #ifndef __COVERITY__
-#define FITS_IN_8_BITS(c) ((sizeof(c) == 1) || !(((WIDEST_UTYPE)(c)) & ~0xFF))
+  /* The '| 0' part ensures a compiler error if c is not integer (like e.g., a
+   * pointer) */
+#define FITS_IN_8_BITS(c) (   (sizeof(c) == 1)                      \
+                           || !(((WIDEST_UTYPE)(c | 0)) & ~0xFF))
 #else
 #define FITS_IN_8_BITS(c) (1)
 #endif