Hi Érico, On Mon, Feb 01, 2021 at 03:56:26PM -0300, Érico Nogueira via Elfutils-devel wrote: > Some C libraries don't provide the GNU version of strerror_r, only the > XSI-compliant one. We use the GNU version when available, since it fits > the code better, and otherwise use the XSI-compliant one.
Could you also mention this bug in the commit message? https://sourceware.org/bugzilla/show_bug.cgi?id=21010 > If possible, I'd like to get this patch in before the release, otherwise > it's an easy one to carry locally. One other comment, but this looks good to go otherwise. > diff --git a/configure.ac b/configure.ac > index 346ab800..baf6faf5 100644 > --- a/configure.ac > +++ b/configure.ac > @@ -428,6 +428,18 @@ AC_CHECK_DECLS([mempcpy],[],[], > > AC_CHECK_FUNCS([process_vm_readv]) > > +AC_CACHE_CHECK([whether C library provides GNU strerror_r], > ac_cv_gnu_strerror_r, [dnl > +old_CFLAGS="$CFLAGS" > +CFLAGS="$CFLAGS -Werror" > +AC_COMPILE_IFELSE([AC_LANG_SOURCE([dnl > +#define _GNU_SOURCE > +#include <string.h> > +char * (*s)(int, char*, size_t) = strerror_r; > +])], ac_cv_gnu_strerror_r=yes, ac_cv_gnu_strerror_r=no) > +CFLAGS="$old_CFLAGS"]) > +AS_IF([test "x$ac_cv_gnu_strerror_r" = "xyes"], > + [AC_DEFINE([HAVE_GNU_STRERROR_R], [1], [Defined if libc has GNU style > strerror_r])]) > + autoconf comes with the following check: - Macro: AC_FUNC_STRERROR_R If strerror_r is available, define HAVE_STRERROR_R, and if it is declared, define HAVE_DECL_STRERROR_R. If it returns a char * message, define STRERROR_R_CHAR_P; otherwise it returns an int error number. The Thread-Safe Functions option of Posix requires strerror_r to return int, but many systems (including, for example, version 2.2.4 of the GNU C Library) return a char * value that is not necessarily equal to the buffer argument. Can we use that instead? > +static const char * > +errnomsg(int error) > +{ > + /* Won't be changed by strerror_r, but not const so compiler doesn't throw > warning */ > + static char unknown[] = "unknown error"; > + > +#ifdef HAVE_GNU_STRERROR_R And use #ifdef STRERROR_R_CHAR_P here? Thanks, Mark
