[Info-vax] no timegm() funtion in C RTL ?

[John Reagan]

"Pierre" <pierre.bru at gmail.com> wrote in message 
news:338fe7d5-a78b-43a9-a56f-7c69c473053b at j23g2000yqc.googlegroups.com...
> hi
>
> I'm looking for the timegm() function in the C RTL but can not find
> it :-/
> http://www.codecogs.com/reference/c/time.h/ctime.php
>
> is this function standard and missing in DECC or is it an exotic
> function non standard function ?
>
> did the test on these config with the same result
> - alpha VMS 7.3-2, Compaq C V6.5-001-48BCD
> - itanium VMS 8.4, HP C V7.3-019-50H5P
>
> TIA,
> Pierre.
>

Here's part of the output from 'man timegm' on one of my Linux boxes

CONFORMING TO
       These functions are non-standard GNU extensions that are  also 
present
       on the BSDs.  Avoid their use; see NOTES.

NOTES
       The  timelocal()  function is equivalent to the POSIX standard 
function
       mktime(3).  There is no reason to ever use it.

       For a portable version of timegm(), set the TZ environment variable 
to
       UTC, call mktime(3) and restore the value of TZ.  Something like

              #include <time.h>
              #include <stdlib.h>

              time_t
              my_timegm(struct tm *tm)
              {
                  time_t ret;
                  char *tz;

                  tz = getenv("TZ");
                  setenv("TZ", "", 1);
                  tzset();
                  ret = mktime(tm);
                  if (tz)
                      setenv("TZ", tz, 1);
                  else
                      unsetenv("TZ");
                  tzset();
                  return ret;
              }