From: Mathieu Desnoyers Date: Fri, 24 Oct 2014 21:13:39 +0000 (-0400) Subject: Fix: silence gcc -Wextra warning X-Git-Tag: v0.7.14~7 X-Git-Url: http://git.liburcu.org/?p=userspace-rcu.git;a=commitdiff_plain;h=6488f70bcf96976bfda4d1836e0cab5ef6f599ff Fix: silence gcc -Wextra warning It appears that just casting to "unsigned long" already has the semantic we are looking for (checked by reading C99 standard and experimentation): it sign-extends smaller signed integers, and does not sign-extend unsigned integers. Signed-off-by: Mathieu Desnoyers --- diff --git a/urcu/compiler.h b/urcu/compiler.h index 074e700..e7817db 100644 --- a/urcu/compiler.h +++ b/urcu/compiler.h @@ -89,12 +89,11 @@ #define caa_is_signed_type(type) ((type) -1 < (type) 0) /* - * Sign-extend to long if needed, and output type is unsigned long. + * Cast to unsigned long, sign-extending if @v is signed. + * Note: casting to a larger type or to same type size keeps the sign of + * the expression being cast (see C99 6.3.1.3). */ -#define caa_cast_long_keep_sign(v) \ - (caa_is_signed_type(__typeof__(v)) ? \ - (unsigned long) (long) (v) : \ - (unsigned long) (v)) +#define caa_cast_long_keep_sign(v) ((unsigned long) (v)) /* * Don't allow compiling with buggy compiler.