[PATCH] Get rid of warning comparision will always evaluate as true

[Stefan Liebler]

Hi,

i get the following warning/error while running make xcheck:
gcc tst-mutexpp6.c -c ...
In file included from tst-mutexpp6.c:45:0:
tst-mutex6.c: In function ‘do_test’:
tst-mutex6.c:38:12: error: the comparison will always evaluate as ‘true’ 
for the address of ‘a’ will never be NULL [-Werror=address]
    if (ATTR != NULL && e == ENOTSUP)
             ^
tst-mutex6.c:49:12: error: the comparison will always evaluate as ‘true’ 
for the address of ‘a’ will never be NULL [-Werror=address]
    if (ATTR != NULL && pthread_mutexattr_destroy (ATTR) != 0)
             ^
cc1: all warnings being treated as errors


In tst-mutexpp6.c ATTR is defined to "a", which is static 
pthread_mutexattr_t and can´t be NULL.
Thus ATTR_NULL is introduced like in tst-mutex1.c,
which is set to false in tst-mutexpp6.c to avoid the warning
and checks ATTR against NULL in the other cases.

Ok to commit?

Bye Stefan

---
2014-12-11  Stefan Liebler  <stli@linux.vnet.ibm.com>

	nptl/tst-mutex6.c
	(ATTR_NULL): New define checks ATTR against NULL.
	(do_test): Use !ATTR_NULL instead of ATTR != NULL.
	nptl/tst-mutexpp6.c (ATTR_NULL): New define.
-------------- next part --------------
diff --git a/nptl/tst-mutex6.c b/nptl/tst-mutex6.c
index 292e3bf..9c11a20 100644
--- a/nptl/tst-mutex6.c
+++ b/nptl/tst-mutex6.c
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <errno.h>
+#include <stdbool.h>
 
 
 #ifndef ATTR
@@ -28,6 +29,9 @@ pthread_mutexattr_t *attr;
 # define ATTR attr
 #endif
 
+#ifndef ATTR_NULL
+# define ATTR_NULL (ATTR == NULL)
+#endif
 
 static int
 do_test (void)
@@ -35,7 +39,7 @@ do_test (void)
   pthread_mutex_t m;
 
   int e = pthread_mutex_init (&m, ATTR);
-  if (ATTR != NULL && e == ENOTSUP)
+  if (!ATTR_NULL && e == ENOTSUP)
     {
       puts ("cannot support selected type of mutexes");
       e = pthread_mutex_init (&m, NULL);
@@ -46,7 +50,7 @@ do_test (void)
       return 1;
     }
 
-  if (ATTR != NULL && pthread_mutexattr_destroy (ATTR) != 0)
+  if (!ATTR_NULL && pthread_mutexattr_destroy (ATTR) != 0)
     {
       puts ("mutexattr_destroy failed");
       return 1;
diff --git a/nptl/tst-mutexpp6.c b/nptl/tst-mutexpp6.c
index 2ddf6b4..87a6ebd 100644
--- a/nptl/tst-mutexpp6.c
+++ b/nptl/tst-mutexpp6.c
@@ -42,4 +42,5 @@ do_test_wrapper (void)
 #define TEST_FUNCTION do_test_wrapper ()
 
 #define ATTR &a
+#define ATTR_NULL false
 #include "tst-mutex6.c"