Re: use of thread-unsafe localeconv in vasprintf

[Bruno Haible]

Simon Josefsson wrote:
> Actually, nl_langinfo is documented to need not be thread-safe:
> 
> http://www.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_09.html

And the same page lists also ecvt(), fcvt(), gcvt() as not being thread-safe.
Argh.

> Btw, can we use the system's native sprintf to get the locale-aware
> decimal point in a thread-safe way?  sprintf is guaranteed to be
> thread-safe, I believe.

Yes, I finally had the same idea. How about this? We don't care much about
efficiency at this point in the code.

Bruno


*** lib/vasnprintf.c    26 Mar 2007 02:15:46 -0000      1.36
--- lib/vasnprintf.c    27 Mar 2007 11:55:11 -0000
***************
*** 511,521 ****
                                  || mantissa > 0.0L || precision > 0)
                                {
                                  const char *point;
!                                 /* Prefer nl_langinfo() over localeconv(),
!                                    since the latter is not multithread-
!                                    safe.  */
! #  if HAVE_NL_LANGINFO
!                                 point = nl_langinfo (RADIXCHAR);
  #  else
                                  point = localeconv () -> decimal_point;
  #  endif
--- 511,527 ----
                                  || mantissa > 0.0L || precision > 0)
                                {
                                  const char *point;
!                                 /* Determine the decimal-point character in a
!                                    multithread-safe way.  We know nl_langinfo
!                                    is multithread-safe on glibc systems,
!                                    otherwise use sprintf, since localeconv()
!                                    is rarely multithread-safe.  */
! #  if HAVE_NL_LANGINFO && __GLIBC__
!                                 point = nl_langinfo (RADIXCHAR);
! #  elif 1
!                                 char pointbuf[5];
!                                 sprintf (pointbuf, "%#.0f", 1.0);
!                                 point = &pointbuf[1];
  #  else
                                  point = localeconv () -> decimal_point;
  #  endif
***************
*** 668,678 ****
                                  || mantissa > 0.0 || precision > 0)
                                {
                                  const char *point;
!                                 /* Prefer nl_langinfo() over localeconv(),
!                                    since the latter is not multithread-
!                                    safe.  */
! #  if HAVE_NL_LANGINFO
!                                 point = nl_langinfo (RADIXCHAR);
  #  else
                                  point = localeconv () -> decimal_point;
  #  endif
--- 674,690 ----
                                  || mantissa > 0.0 || precision > 0)
                                {
                                  const char *point;
!                                 /* Determine the decimal-point character in a
!                                    multithread-safe way.  We know nl_langinfo
!                                    is multithread-safe on glibc systems,
!                                    otherwise use sprintf, since localeconv()
!                                    is rarely multithread-safe.  */
! #  if HAVE_NL_LANGINFO && __GLIBC__
!                                 point = nl_langinfo (RADIXCHAR);
! #  elif 1
!                                 char pointbuf[5];
!                                 sprintf (pointbuf, "%#.0f", 1.0);
!                                 point = &pointbuf[1];
  #  else
                                  point = localeconv () -> decimal_point;
  #  endif