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CTIME(3P)                  POSIX Programmer's Manual                 CTIME(3P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
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, repre-
       senting 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  struc-
       ture  and an array of char. Execution of any of the functions may over-
       write 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  compati-
       bility  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(), strf-
       time(), 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 .

IEEE/The Open Group                  2003                            CTIME(3P)