Does localtime_r(...) use pthread library (LinuxThreads or NPTL)?

["Bo Xie" <xiebopublic at gmail dot com>]

Hi all,

Does localtime_r(...) use pthread library (LinuxThreads or NPTL)?

I've checked glibc 2.4 source code.  But I don't know what "weak_alias
(__localtime_r, localtime_r)" means. I really want to know how to
implement thread-safe glibc.
------localtime.c---
#include <time.h>

/* The C Standard says that localtime and gmtime return the same pointer.  */
struct tm _tmbuf;


/* Return the `struct tm' representation of *T in local time,
  using *TP to store the result.  */
struct tm *
__localtime_r (t, tp)
    const time_t *t;
    struct tm *tp;
{
 return __tz_convert (t, 1, tp);
}
weak_alias (__localtime_r, localtime_r)


/* Return the `struct tm' representation of *T in local time.  */
struct tm *
localtime (t)
    const time_t *t;
{
 return __tz_convert (t, 1, &_tmbuf);
}
libc_hidden_def (localtime)
-----------------------

Thanks!

Best Regards,
Xie, Bo