On Sat, Oct 14, 2006 at 02:13:38PM +0100, Neil Jerram wrote:
> [EMAIL PROTECTED] (Ludovic Court?s) writes:
>
> > As for this:
> >
> > async.c: In function 'scm_i_queue_async_cell':
> > async.c:250: warning: ignoring return value of 'write', declared with
> > attribute warn_unused_result
> >
> > I don't really understand what this code does, but I have the feeling
> > that line 250 could be rewritten this way:
> >
> > SCM_SYSCALL ((void)write (sleep_fd, &dummy, 1));
> >
> > Can somebody familiar with this comment?
>
> Agreed. Stanislav, can you try this and confirm whether it removes
> the warning you are getting?
New compiller is a too smart for it ;)
--
$ make
...
gcc -DHAVE_CONFIG_H -I. -I. -I.. -I.. -I.. -pthread -pipe -Wall -O2
-march=i686 -mtune=pentium4 -Wall -Wmissing-prototypes -Werror -c async.c
-fPIC -DPIC -o .libs/libguile_la-async.o
cc1: warnings being treated as errors
async.c: In function 'scm_i_queue_async_cell':
async.c:250: warning: ignoring return value of 'write', declared with
attribute warn_unused_result
make[1]: *** [libguile_la-async.lo] Ошибка 1
make[1]: Leaving directory `/mnt/archive/RPM/BUILD/guile-1.8.1/libguile'
make: *** [all] Ошибка 2
$ grep SCM_SYSCALL async.c
SCM_SYSCALL((void)write (sleep_fd, &dummy, 1));
--
I think, you will have to create an explicit tests:
--
$ gcc-4.1 -O1 l.c
l.c: In function 'main':
l.c:6: warning: ignoring return value of 'write', declared with attribute
warn_unused_result
$ cat l.c
#include <unistd.h>
int main()
{
char c;
(void)write(1,&c,1);
return 0;
}
$ gcc-4.1 -O1 l0.c
$ cat l0.c
#include <unistd.h>
int main()
{
char c;
if(write(1,&c,1));
return 0;
}
$ gcc-4.1 -O1 l1.c
$ cat l1.c
#include <unistd.h>
void ignore(int retcode)
{
}
int main()
{
char c;
ignore(write(1,&c,1));
return 0;
}
The best solution is to create a simple wrapper like this:
--
$ gcc -O1 l2.c
[EMAIL PROTECTED] zzz]$ cat l2.c
#include <stdlib.h>
#include <unistd.h>
#include <error.h>
#include <errno.h>
#define CHECK_OR_IGNORE(x) if (x) error(EXIT_FAILURE,errno,#x)
int main()
{
char c;
CHECK_OR_IGNORE(write(1,&c,1));
return 0;
}
--
--
With best regards
Stanislav Ievlev;
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