Re: fix some gcc warnings

[Bruno Haible]

Pádraig Brady wrote:
> > 2016-10-16  Bruno Haible  
> > 
> > Fix some "gcc -Wall" warnings.
> > * tests/test-ffsl.c (main): Use variable x, not i.
> > * tests/test-posix_spawn3.c (parent_main): Consider the return value of
> > freopen.
> > * tests/test-sethostname1.c (main): Explicitly ignore the return value
> > of sethostname.
>
> +1
> thanks

OK, I pushed this.

Re: fix some gcc warnings

[Pádraig Brady]

On 16/10/16 16:01, Bruno Haible wrote:
> Hi,
> 
> When I compile a gnulib testdir with "gcc -Wall", I see the following warnings
> (among others):
> 
> test-ffsl.c: In function 'main':
> test-ffsl.c:44:12: warning: unused variable 'x' [-Wunused-variable]
> 
> test-posix_spawn3.c: In function 'parent_main':
> test-posix_spawn3.c:78:11: warning: ignoring return value of 'freopen', 
> declared with attribute warn_unused_result [-Wunused-result]
> 
> test-sethostname1.c: In function 'main':
> test-sethostname1.c:34:17: warning: ignoring return value of 'sethostname', 
> declared with attribute warn_unused_result [-Wunused-result]
> 
> Here's a proposed fix for them.
> 
> 
> 2016-10-16  Bruno Haible  
> 
>   Fix some "gcc -Wall" warnings.
>   * tests/test-ffsl.c (main): Use variable x, not i.
>   * tests/test-posix_spawn3.c (parent_main): Consider the return value of
>   freopen.
>   * tests/test-sethostname1.c (main): Explicitly ignore the return value
>   of sethostname.
> 
> diff --git a/tests/test-ffsl.c b/tests/test-ffsl.c
> index e903509..117bc4a 100644
> --- a/tests/test-ffsl.c
> +++ b/tests/test-ffsl.c
> @@ -44,8 +44,8 @@ main (int argc, char *argv[])
>long int x;
>int i;
>  
> -  for (i = -128; i <= 128; i++)
> -ASSERT (ffsl (i) == naive (i));
> +  for (x = -128; x <= 128; x++)
> +ASSERT (ffsl (x) == naive (x));
>for (i = 0; i < NBITS; i++)
>  {
>ASSERT (ffsl (1UL << i) == naive (1UL << i));
> diff --git a/tests/test-posix_spawn3.c b/tests/test-posix_spawn3.c
> index 90745fd..f2a699c 100644
> --- a/tests/test-posix_spawn3.c
> +++ b/tests/test-posix_spawn3.c
> @@ -75,7 +75,11 @@ parent_main (void)
>  }
>  
>/* Avoid reading from our stdin, as it could block.  */
> -  freopen ("/dev/null", "rb", stdin);
> +  if (freopen ("/dev/null", "rb", stdin) == NULL)
> +{
> +  perror ("cannot redirect stdin");
> +  return 1;
> +}
>  
>/* Test whether posix_spawn_file_actions_addopen with this file name
>   actually works, but spawning a child that reads from this file.  */
> diff --git a/tests/test-sethostname1.c b/tests/test-sethostname1.c
> index 5ed6a83..08441f3 100644
> --- a/tests/test-sethostname1.c
> +++ b/tests/test-sethostname1.c
> @@ -30,8 +30,11 @@ main ()
>/* Some code that has a link-time dependency to the sethostname() function
>   and that is likely not optimized away by compilers.  */
>if (do_dangerous_things)
> -/* Never executed.  */
> -sethostname ("oprah", 5);
> +{
> +  /* Never executed.  */
> +  int ret = sethostname ("oprah", 5);
> +  (void) ret;
> +}
>  
>return 0;
>  }
> 
> 
> 

+1
thanks

fix some gcc warnings

[Bruno Haible]

Hi,

When I compile a gnulib testdir with "gcc -Wall", I see the following warnings
(among others):

test-ffsl.c: In function 'main':
test-ffsl.c:44:12: warning: unused variable 'x' [-Wunused-variable]

test-posix_spawn3.c: In function 'parent_main':
test-posix_spawn3.c:78:11: warning: ignoring return value of 'freopen', 
declared with attribute warn_unused_result [-Wunused-result]

test-sethostname1.c: In function 'main':
test-sethostname1.c:34:17: warning: ignoring return value of 'sethostname', 
declared with attribute warn_unused_result [-Wunused-result]

Here's a proposed fix for them.


2016-10-16  Bruno Haible  

Fix some "gcc -Wall" warnings.
* tests/test-ffsl.c (main): Use variable x, not i.
* tests/test-posix_spawn3.c (parent_main): Consider the return value of
freopen.
* tests/test-sethostname1.c (main): Explicitly ignore the return value
of sethostname.

diff --git a/tests/test-ffsl.c b/tests/test-ffsl.c
index e903509..117bc4a 100644
--- a/tests/test-ffsl.c
+++ b/tests/test-ffsl.c
@@ -44,8 +44,8 @@ main (int argc, char *argv[])
   long int x;
   int i;
 
-  for (i = -128; i <= 128; i++)
-ASSERT (ffsl (i) == naive (i));
+  for (x = -128; x <= 128; x++)
+ASSERT (ffsl (x) == naive (x));
   for (i = 0; i < NBITS; i++)
 {
   ASSERT (ffsl (1UL << i) == naive (1UL << i));
diff --git a/tests/test-posix_spawn3.c b/tests/test-posix_spawn3.c
index 90745fd..f2a699c 100644
--- a/tests/test-posix_spawn3.c
+++ b/tests/test-posix_spawn3.c
@@ -75,7 +75,11 @@ parent_main (void)
 }
 
   /* Avoid reading from our stdin, as it could block.  */
-  freopen ("/dev/null", "rb", stdin);
+  if (freopen ("/dev/null", "rb", stdin) == NULL)
+{
+  perror ("cannot redirect stdin");
+  return 1;
+}
 
   /* Test whether posix_spawn_file_actions_addopen with this file name
  actually works, but spawning a child that reads from this file.  */
diff --git a/tests/test-sethostname1.c b/tests/test-sethostname1.c
index 5ed6a83..08441f3 100644
--- a/tests/test-sethostname1.c
+++ b/tests/test-sethostname1.c
@@ -30,8 +30,11 @@ main ()
   /* Some code that has a link-time dependency to the sethostname() function
  and that is likely not optimized away by compilers.  */
   if (do_dangerous_things)
-/* Never executed.  */
-sethostname ("oprah", 5);
+{
+  /* Never executed.  */
+  int ret = sethostname ("oprah", 5);
+  (void) ret;
+}
 
   return 0;
 }

thread: fix some gcc warnings

[Bruno Haible]

The statement
  gl_thread_t t = gl_thread_self ();
gives a gcc warning about assignment from a pointer to an integer. This fixes
it:


2011-07-08  Bruno Haible  br...@clisp.org

thread: Avoid gcc warnings when using gl_thread_self().
* lib/glthread/thread.h (gl_thread_self): Return a pthread_t, not a
'void *'.
(gl_thread_self_pointer): Update.

--- lib/glthread/thread.h.orig  Fri Jul  8 13:22:25 2011
+++ lib/glthread/thread.h   Fri Jul  8 13:11:25 2011
@@ -161,9 +161,9 @@
 extern const gl_thread_t gl_null_thread;
 # else
 #  define gl_thread_self() \
- (pthread_in_use () ? (void *) pthread_self () : NULL)
+ (pthread_in_use () ? pthread_self () : (pthread_t) NULL)
 #  define gl_thread_self_pointer() \
- gl_thread_self ()
+ (pthread_in_use () ? (void *) pthread_self () : NULL)
 # endif
 # define gl_thread_exit(RETVAL) \
 (pthread_in_use () ? pthread_exit (RETVAL) : 0)

-- 
In memoriam Jean Moulin http://en.wikipedia.org/wiki/Jean_Moulin

Re: thread: fix some gcc warnings

[Eric Blake]

On 07/08/2011 05:27 AM, Bruno Haible wrote:
 The statement
   gl_thread_t t = gl_thread_self ();
 gives a gcc warning about assignment from a pointer to an integer. This fixes
 it:
 
 
 2011-07-08  Bruno Haible  br...@clisp.org
 
   thread: Avoid gcc warnings when using gl_thread_self().
   * lib/glthread/thread.h (gl_thread_self): Return a pthread_t, not a
   'void *'.
   (gl_thread_self_pointer): Update.
 
 --- lib/glthread/thread.h.origFri Jul  8 13:22:25 2011
 +++ lib/glthread/thread.h Fri Jul  8 13:11:25 2011
 @@ -161,9 +161,9 @@
  extern const gl_thread_t gl_null_thread;
  # else
  #  define gl_thread_self() \
 - (pthread_in_use () ? (void *) pthread_self () : NULL)
 + (pthread_in_use () ? pthread_self () : (pthread_t) NULL)

This not portable.  POSIX allows pthread_t to be a non-pointer type, so
you can't necessarily cast NULL to pthread_t.

-- 
Eric Blake   ebl...@redhat.com+1-801-349-2682
Libvirt virtualization library http://libvirt.org



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Re: thread: fix some gcc warnings

[Bruno Haible]

Eric Blake wrote:
  - (pthread_in_use () ? (void *) pthread_self () : NULL)
  + (pthread_in_use () ? pthread_self () : (pthread_t) NULL)
 
 This not portable.  POSIX allows pthread_t to be a non-pointer type, so
 you can't necessarily cast NULL to pthread_t.

Yes, and the only platform that defines pthread_t to a non-scalar type
is pthreads-win32, and it is handled 5 lines above that code.

Bruno
-- 
In memoriam Jean Moulin http://en.wikipedia.org/wiki/Jean_Moulin