Originální popis anglicky:
asctime, asctime_r - convert date and time to a string
Návod, kniha: POSIX Programmer's Manual
#include <time.h>
char *asctime(const struct tm *
timeptr);
char *asctime_r(const struct tm *restrict tm, char
*restrict buf);
For
asctime(): 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
asctime() function shall convert the broken-down time in the
structure pointed to by
timeptr into a string in the form:
Sun Sep 16 01:03:52 1973\n\0
using the equivalent of the following algorithm:
char *asctime(const struct tm *timeptr)
{
static char wday_name[7][3] = {
"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
};
static char mon_name[12][3] = {
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
};
static char result[26];
sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
wday_name[timeptr->tm_wday],
mon_name[timeptr->tm_mon],
timeptr->tm_mday, timeptr->tm_hour,
timeptr->tm_min, timeptr->tm_sec,
1900 + timeptr->tm_year);
return result;
}
The
tm structure is defined in the
<time.h> header.
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 type
char. Execution of any of the functions
may overwrite the information returned in either of these objects by any of
the other functions.
The
asctime() function need not be reentrant. A function that is not
required to be reentrant is not required to be thread-safe.
The
asctime_r() function shall convert the broken-down time in the
structure pointed to by
tm into a string (of the same form as that
returned by
asctime()) that is placed in the user-supplied buffer
pointed to by
buf (which shall contain at least 26 bytes) and then
return
buf.
Upon successful completion,
asctime() shall return a pointer to the
string.
Upon successful completion,
asctime_r() shall return a pointer to a
character string containing the date and time. This string is pointed to by
the argument
buf. If the function is unsuccessful, it shall return
NULL.
No errors are defined.
The following sections are informative.
None.
Values for the broken-down time structure can be obtained by calling
gmtime() or
localtime(). This function is included for
compatibility with older implementations, and does not support localized date
and time formats. Applications should use
strftime() to achieve maximum
portability.
The
asctime_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.
None.
None.
clock() ,
ctime() ,
difftime() ,
gmtime() ,
localtime() ,
mktime() ,
strftime() ,
strptime() ,
time() ,
utime() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<time.h>
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
.
