Fix unused malloc return value warning

Message ID fe65df92-c224-aab5-33b1-a5f7ba5a7b6b@gmail.com
State New
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Series
  • Fix unused malloc return value warning
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Commit Message

François Dumont Aug. 29, 2019, 7:54 p.m.
Hi

     I am having this warning:

/home/fdt/dev/gcc/git/libstdc++-v3/testsuite/util/testsuite_performance.h:170: 
attention: ignoring return value of « void* malloc(size_t) » declared 
with attribute « warn_unused_result » [-Wunused-result]
   170 |       malloc(0); // Needed for some implementations.

     Ok to fix it with attached patch ?

     It seems trivial but I wonder if I shouldn't keep the malloc 
returned pointer and free it properly ?

     Or maybe just remove the malloc cause there is not clear comment 
explaining why it's needed and I haven't found much in SVN audit trail.

     * testsuite_files/util/testsuite_performance.h
     (resource_counter::start): Ignore unused malloc(0) result.

François

Comments

Jonathan Wakely Aug. 30, 2019, 1:34 p.m. | #1
On 29/08/19 21:54 +0200, François Dumont wrote:
>Hi

>

>    I am having this warning:

>

>/home/fdt/dev/gcc/git/libstdc++-v3/testsuite/util/testsuite_performance.h:170: 

>attention: ignoring return value of « void* malloc(size_t) » declared 

>with attribute « warn_unused_result » [-Wunused-result]

>  170 |       malloc(0); // Needed for some implementations.

>

>    Ok to fix it with attached patch ?


OK for trunk.

>    It seems trivial but I wonder if I shouldn't keep the malloc 

>returned pointer and free it properly ?


It's not causing any problems (it's only the testsuite) so let's not
worry about it.

>    Or maybe just remove the malloc cause there is not clear comment 

>explaining why it's needed and I haven't found much in SVN audit 

>trail.


The comment says it's needed, so let's assume that's true.

>    * testsuite_files/util/testsuite_performance.h

>    (resource_counter::start): Ignore unused malloc(0) result.

>

>François

>


>diff --git a/libstdc++-v3/testsuite/util/testsuite_performance.h b/libstdc++-v3/testsuite/util/testsuite_performance.h

>index 556c78159be..8abc77cf31a 100644

>--- a/libstdc++-v3/testsuite/util/testsuite_performance.h

>+++ b/libstdc++-v3/testsuite/util/testsuite_performance.h

>@@ -167,7 +167,7 @@ namespace __gnu_test

>     {

>       if (getrusage(who, &rusage_begin) != 0 )

> 	memset(&rusage_begin, 0, sizeof(rusage_begin));

>-      malloc(0); // Needed for some implementations.

>+      void* p __attribute__((unused)) = malloc(0); // Needed for some implementations.

>       allocation_begin = mallinfo();

>     }

> 

>

Patch

diff --git a/libstdc++-v3/testsuite/util/testsuite_performance.h b/libstdc++-v3/testsuite/util/testsuite_performance.h
index 556c78159be..8abc77cf31a 100644
--- a/libstdc++-v3/testsuite/util/testsuite_performance.h
+++ b/libstdc++-v3/testsuite/util/testsuite_performance.h
@@ -167,7 +167,7 @@  namespace __gnu_test
     {
       if (getrusage(who, &rusage_begin) != 0 )
 	memset(&rusage_begin, 0, sizeof(rusage_begin));
-      malloc(0); // Needed for some implementations.
+      void* p __attribute__((unused)) = malloc(0); // Needed for some implementations.
       allocation_begin = mallinfo();
     }