Re: [PATCH] man/man3/pthread_attr_init.3: Replace errc

["Dr. David Alan Gilbert" <dave@treblig.org>]

* Alejandro Colomar (alx@kernel.org) wrote:
> Hi Dave,

Hi Alex,

> On Wed, Aug 20, 2025 at 02:27:25AM +0100, dave@treblig.org wrote:
> > From: "Dr. David Alan Gilbert" <dave@treblig.org>
> > 
> > The pthread_attr_init.3 example uses 'errc' to exit on an error
> > printing the error code.  However, 'errc' is a BSDism that Linux
> > doesn't (and has never?) have.

> Libbsd provides a compatbility layer to provide errc(3bsd) on Linux (and
> many POSIX systems).  libbsd is available in many distros (in Debian,
> you should install libbsd-dev).  BTW, it would be nice if glibc decided
> to pick this API eventually.

To use that we'd still need to change to:
       #include <bsd/err.h>
and tell people to link with -lbsd

TBH using BSD only things in a Linux manpage with a _GNU_SOURCE define
seems odd.  The err()/errc()/errx() family of calls seems to be pretty
obscure, most [linux] people I checked with had never used them.
But at least err/errx are in normal glibc.

Dave

> 
> Have a lovely day!
> Alex
> 
> > Replace it by 'errx' with a strerror() call.
> > 
> > Signed-off-by: Dr. David Alan Gilbert <dave@treblig.org>
> > ---
> >  man/man3/pthread_attr_init.3 | 31 ++++++++++++++++---------------
> >  1 file changed, 16 insertions(+), 15 deletions(-)
> > 
> > diff --git a/man/man3/pthread_attr_init.3 b/man/man3/pthread_attr_init.3
> > index e9058b8fe..9d0783e54 100644
> > --- a/man/man3/pthread_attr_init.3
> > +++ b/man/man3/pthread_attr_init.3
> > @@ -153,6 +153,7 @@ .SS Program source
> >  #include <pthread.h>
> >  #include <stdio.h>
> >  #include <stdlib.h>
> > +#include <string.h>
> >  #include <unistd.h>
> >  \&
> >  static void
> > @@ -165,7 +166,7 @@ .SS Program source
> >  \&
> >      s = pthread_attr_getdetachstate(attr, &i);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getdetachstate");
> > +        errx(EXIT_FAILURE, "pthread_attr_getdetachstate: %s", strerror(s));
> >      printf("%sDetach state        = %s\[rs]n", prefix,
> >             (i == PTHREAD_CREATE_DETACHED) ? "PTHREAD_CREATE_DETACHED" :
> >             (i == PTHREAD_CREATE_JOINABLE) ? "PTHREAD_CREATE_JOINABLE" :
> > @@ -173,7 +174,7 @@ .SS Program source
> >  \&
> >      s = pthread_attr_getscope(attr, &i);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getscope");
> > +        errx(EXIT_FAILURE, "pthread_attr_getscope: %s", strerror(s));
> >      printf("%sScope               = %s\[rs]n", prefix,
> >             (i == PTHREAD_SCOPE_SYSTEM)  ? "PTHREAD_SCOPE_SYSTEM" :
> >             (i == PTHREAD_SCOPE_PROCESS) ? "PTHREAD_SCOPE_PROCESS" :
> > @@ -181,7 +182,7 @@ .SS Program source
> >  \&
> >      s = pthread_attr_getinheritsched(attr, &i);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getinheritsched");
> > +        errx(EXIT_FAILURE, "pthread_attr_getinheritsched: %s", strerror(s));
> >      printf("%sInherit scheduler   = %s\[rs]n", prefix,
> >             (i == PTHREAD_INHERIT_SCHED)  ? "PTHREAD_INHERIT_SCHED" :
> >             (i == PTHREAD_EXPLICIT_SCHED) ? "PTHREAD_EXPLICIT_SCHED" :
> > @@ -189,7 +190,7 @@ .SS Program source
> >  \&
> >      s = pthread_attr_getschedpolicy(attr, &i);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getschedpolicy");
> > +        errx(EXIT_FAILURE, "pthread_attr_getschedpolicy: %s", strerror(s));
> >      printf("%sScheduling policy   = %s\[rs]n", prefix,
> >             (i == SCHED_OTHER) ? "SCHED_OTHER" :
> >             (i == SCHED_FIFO)  ? "SCHED_FIFO" :
> > @@ -198,17 +199,17 @@ .SS Program source
> >  \&
> >      s = pthread_attr_getschedparam(attr, &sp);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getschedparam");
> > +        errx(EXIT_FAILURE, "pthread_attr_getschedparam: %s", strerror(s));
> >      printf("%sScheduling priority = %d\[rs]n", prefix, sp.sched_priority);
> >  \&
> >      s = pthread_attr_getguardsize(attr, &v);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getguardsize");
> > +        errx(EXIT_FAILURE, "pthread_attr_getguardsize: %s", strerror(s));
> >      printf("%sGuard size          = %zu bytes\[rs]n", prefix, v);
> >  \&
> >      s = pthread_attr_getstack(attr, &stkaddr, &v);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_attr_getstack");
> > +        errx(EXIT_FAILURE, "pthread_attr_getstack: %s", strerror(s));
> >      printf("%sStack address       = %p\[rs]n", prefix, stkaddr);
> >      printf("%sStack size          = %#zx bytes\[rs]n", prefix, v);
> >  }
> > @@ -225,7 +226,7 @@ .SS Program source
> >  \&
> >      s = pthread_getattr_np(pthread_self(), &gattr);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_getattr_np");
> > +        errx(EXIT_FAILURE, "pthread_getattr_np: %s", strerror(s));
> >  \&
> >      printf("Thread attributes:\[rs]n");
> >      display_pthread_attr(&gattr, "\[rs]t");
> > @@ -255,37 +256,37 @@ .SS Program source
> >  \&
> >          s = pthread_attr_init(&attr);
> >          if (s != 0)
> > -            errc(EXIT_FAILURE, s, "pthread_attr_init");
> > +            errx(EXIT_FAILURE, "pthread_attr_init: %s", strerror(s));
> >  \&
> >          s = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
> >          if (s != 0)
> > -            errc(EXIT_FAILURE, s, "pthread_attr_setdetachstate");
> > +            errx(EXIT_FAILURE, "pthread_attr_setdetachstate: %s", strerror(s));
> >  \&
> >          s = pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
> >          if (s != 0)
> > -            errc(EXIT_FAILURE, s, "pthread_attr_setinheritsched");
> > +            errx(EXIT_FAILURE, "pthread_attr_setinheritsched: %s", strerror(s));
> >  \&
> >          stack_size = strtoul(argv[1], NULL, 0);
> >  \&
> >          s = posix_memalign(&sp, sysconf(_SC_PAGESIZE), stack_size);
> >          if (s != 0)
> > -            errc(EXIT_FAILURE, s, "posix_memalign");
> > +            errx(EXIT_FAILURE, "posix_memalign: %s", strerror(s));
> >  \&
> >          printf("posix_memalign() allocated at %p\[rs]n", sp);
> >  \&
> >          s = pthread_attr_setstack(&attr, sp, stack_size);
> >          if (s != 0)
> > -            errc(EXIT_FAILURE, s, "pthread_attr_setstack");
> > +            errx(EXIT_FAILURE, "pthread_attr_setstack: %s", strerror(s));
> >      }
> >  \&
> >      s = pthread_create(&thr, attrp, &thread_start, NULL);
> >      if (s != 0)
> > -        errc(EXIT_FAILURE, s, "pthread_create");
> > +        errx(EXIT_FAILURE, "pthread_create: %s", strerror(s));
> >  \&
> >      if (attrp != NULL) {
> >          s = pthread_attr_destroy(attrp);
> >          if (s != 0)
> > -            errc(EXIT_FAILURE, s, "pthread_attr_destroy");
> > +            errx(EXIT_FAILURE, "pthread_attr_destroy: %s", strerror(s));
> >      }
> >  \&
> >      pause();    /* Terminates when other thread calls exit() */
> > -- 
> > 2.50.1
> > 
> 
> -- 
> <https://www.alejandro-colomar.es/>


-- 
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