trusty (3) ctime_r.3posix.gz

NAME

       ctime, ctime_r - convert a time value to a date and time string

SYNOPSIS

       #include <time.h>

       char *ctime(const time_t *clock);

       char *ctime_r(const time_t *clock, char *buf);

DESCRIPTION

       For ctime():   The functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is unintentional. This volume  of
       IEEE Std 1003.1-2001 defers to the ISO C standard.

       The  ctime()  function shall convert the time pointed to by clock, representing time in seconds since the
       Epoch, to local time in the form of a string. It shall be equivalent to:

              asctime(localtime(clock))

       The asctime(), ctime(), gmtime(), and localtime() functions shall return values  in  one  of  two  static
       objects:  a  broken-down  time  structure  and  an  array  of char. Execution of any of the functions may
       overwrite the information returned in either of these objects by any of the other functions.

       The ctime() function need not be reentrant. A function that is  not  required  to  be  reentrant  is  not
       required to be thread-safe.

       The  ctime_r()  function shall convert the calendar time pointed to by clock to local time in exactly the
       same form as ctime() and put the string into the array pointed to by buf (which  shall  be  at  least  26
       bytes in size) and return buf.

       Unlike ctime(), the thread-safe version ctime_r() is not required to set tzname.

RETURN VALUE

       The  ctime()  function  shall  return  the pointer returned by asctime() with that broken-down time as an
       argument.

       Upon successful completion, ctime_r() shall return a pointer to the string pointed to  by  buf.  When  an
       error is encountered, a null pointer shall be returned.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Values for the broken-down time structure can be obtained by calling gmtime() or localtime(). The ctime()
       function is included for compatibility with older implementations, and does not  support  localized  date
       and time formats.  Applications should use the strftime() function to achieve maximum portability.

       The  ctime_r()  function  is  thread-safe  and  shall  return values in a user-supplied buffer instead of
       possibly using a static data area that may be overwritten by each call.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       asctime() , clock() , difftime() , gmtime() , localtime() , mktime() , strftime() , strptime() , time() ,
       utime() , the Base Definitions volume of IEEE Std 1003.1-2001, <time.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc and The Open Group. In the event of any discrepancy between this version and the  original  IEEE  and
       The  Open  Group  Standard,  the  original  IEEE and The Open Group Standard is the referee document. The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .