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 correspond-
       ing 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, 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 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(), 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 Technol-
       ogy -- 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)