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wcsftime(3) [osf1 man page]

strftime(3)						     Library Functions Manual						       strftime(3)

NAME
strftime, wcsftime - Converts a date and time to a string or wide-character string LIBRARY
Standard C Library (libc) SYNOPSIS
#include <time.h> size_t strftime( char *s, size_t maxsize, const char *format, const struct tm *timeptr); #include <wchar.h> size_t wcsftime( wchar_t *wcs, size_t maxsize, const wchar_t *format, const struct tm *timeptr); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: strftime(), wcsftime(): XSH5.0 Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Points to the array containing the output date and time string. Specifies the maximum number of bytes or wide characters to be written to the array pointed to by the s or wcs parameter. Points to a sequence of characters that specify the format of the date and time to be written to the output string or wide-character string. See the DESCRIPTION section for more information. Points to a type tm structure that contains broken-down time information. Points to the wide-character array containing the output date and time string. DESCRIPTION
The strftime() function places characters into the array pointed to by the s parameter as controlled by the string pointed to by the format parameter. Local time zone information is used as though the strftime() function called the tzset() function. Time information used in this subroutine is fetched from space containing type tm structure data, which is defined in the time.h include file. The type tm structure must contain the time information used by this subroutine to construct the time and date string. The format string consists of characters that represent zero or more conversion specifications and ordinary characters that represent the date and time values and null string terminator. Each conversion specification starts with a % (percent sign) character followed by one or more characters that determine how the conversion specification constructs the formatted string. Any ordinary characters (including the terminating null character) in the format string are copied unchanged into the s array. When copying between objects that overlap, func- tion behavior is undefined. No more than the number of bytes specified by the maxsize parameter are written to the array (including the terminating null character). The strftime() function replaces the conversion specification with the appropriately formatted date or time value. Ordinary characters are written to the output buffer unchanged. Each conversion specification is replaced by the appropriate characters as described later in this section. The appropriate characters are determined by the LC_TIME category of the current locale and by values specified by the type tm structure pointed to by the timeptr parame- ter. The wcsftime() function is equivalent to the strftime() function, except that: The wcs parameter points to the initial element of an array of wide characters into which the generated output is to be placed. The maxsize parameter indicates the maximum number of wide characters to be placed in wcs. The format parameter is a wide-character string and the conversion specifications are replaced by corresponding sequences of wide characters. In the obsolete version of the wcsftime() function (which conforms to Issue 4 Revision 2 and earlier versions of the XSH specifica- tion), the format parameter is defined to be const char* rather than const wchar_t* as currently required by the ISO C standard and XSH Issue 5. See standards(5) for more information about using compile-time options and compilation environments to conform to dif- ferent levels of industry standards. The return value indicates the number of wide characters placed in wcs. The format parameter has the following syntax. Each conversion specification that is included in the format parameter starts with a percent sign (%). In portable applications, the % character is immediately followed by format-code. [ordinary-text] [%[[-|0]width][.precision]format-code [ordinary-text]]... In this syntax: Text that is copied to the output parameter with no changes. [Tru64 UNIX] A decimal digit string that specifies the minimum field width. If the width of the item equals or exceeds the minimum field width, the minimum is ignored. If the width of the item is less than the mini- mum field width, the function justifies and pads the item. The optional - (minus sign) or 0 (zero digit) control the justification and pad- ding as follows: Item is right justified and spaces are added to the beginning of the item to fill the minimum width. Item is left justi- fied and spaces are added to the end of the item to fill the minimum width. Item is right justified and zeros are added to the beginning of the item to fill the minimum width. [Tru64 UNIX] A decimal string that specifies the minimum number of digits to appear for the d, H, I, j, m, M, o, S, U, w, W, y, and Y conversion formats and the maximum number of characters to used from the a, A, b, B, c, D, E, h, n, N, p, r, t, T, x, X, Z, and % conversion formats. [Tru64 UNIX] If no field width or precision is specified for the d, H, I, m, M, S, U, W, or y conversion character, a default pre- cision of .2 is used. If no field width or precision is specified for the j conversion character, a default precision of 3 is used. A conversion-code character that specifies the date and time conversion to perform. Some conversion-code characters can be preceded by an E or an O modifier. The E modifier indicates that an alternative date and time representation should be used if one is defined by the locale in which the application is running. Th O modifier indicates that alternative numeric symbols should be used if they are defined by the locale in which the application is running. If the application specifies a modified conversion-code for format- code and the application runs in a locale that does not define the alternative conversion, conversion proceeds as though the conver- sion-code character were unmodified. The following list describes the modified and unmodified conversion-code characters: The short day of the week is output as a string as defined for the current locale (Mon, for example). The long day of the week is output as defined for the current locale (Monday, for example). The short month is output as a string as defined for the current locale (Jan, for example). The long month is output as a string as defined for the current locale (January, for example). The date and time is output with the default date and time as defined for the current locale. The century is output as a decimal number in the range 00 to 99. The day of the month is output as a number between 01 and 31. The format is fixed to return %m/%d/%y. (For example, 20 Jun 1990 will return 06/20/90.) The day of the month is output as a number between 1 and 31 in a 2-digit field with leading space fill. Specifies the locale's alternative appropriate date and time representation. Specifies the name of the base year (period) in the locale's alternative representation. Specifies the locale's alternative date representation. Specifies the locale's alternative time representation. Specifies the offset from %EC (year only) in the locale's alternative representation. Specifies the full alternative year representation. The hour of the day is output as a number between 00 and 23. Same as b. The hour of the day is output as a number between 01 and 12. The Julian day of the year is output as a number between 001 and 366. The month of the year is output as a number between 01 and 12. The minute is output as a number between 00 and 59. Only a newline character is output. The locale-dependent Emperor/Era name is output. The locale-dependent Emperor/Era year is output. Specifies the day of the month using the locale's alternative numeric symbols. Specifies the day of the month using the locale's alternative numeric symbols. Specifies the hour (24-hour clock) using the locale's alternative numeric symbols. Specifies the hour (12-hour clock) using the locale's alternative numeric symbols. Specifies the month using the locale's alternative numeric symbols. Specifies the minutes using the locale's alternative numeric symbols. Specifies the seconds using the locale's alternative numeric symbols. Specifies the weekday as a number in the locale's alternative representation (Monday=1). Specifies the week number of the year (Sunday as the first day of the week) using the locale's alternative numeric symbols. Specifies the week number of the year (Monday as the first day of the week, rules corresponding to %V), using the locale's alternative numeric symbols. Specifies the week day as a number in the locale's alternative representation (Sunday = 0). Specifies the week number of the year (Monday as the first day of the week) using the locale's alternative numeric symbols. Specifies the year (offset from %C) by using the locale's alternative numeric sym- bols. The AM or PM indicator is output as a string specified for the current locale. The time in AM/PM notation is output, accord- ing to British/US conventions (%I:%M:%S [AM|PM]). The time in hours (24-hour clock) and minutes (%H:%M). The second is output as a number between 00 and 61. Only a tab character is output. The time is output as %H:%M:%S. Specifies the weekday as a decimal num- ber [1,7], with 1 representing Monday. The week number of the year (Sunday as the first day of the week). Output format is a deci- mal number between 0 and 53. The week number of the year (Monday as the first day of the week). Output format is a decimal number between 1 and 53. If the week containing January 1 has four or more days in the new year, then it is considered week 1; otherwise, it is the last week of the previous year, and the next week is week 1. The day of the week is output as a number between 0 (Sunday) and 6. The week number of the year (Monday as the first day of the week). Output format is a decimal number between 0 and 53. The short date is output in the format specified for the current locale. The time is output in the format specified for the current locale. The year is output as a number (without the century) between 00 and 99. Because this conversion code relies on a two-digit representation of the year, it is not recommended. Use Y instead. The year is output as a number (with the century) between 0000 and 9999. The (standard time or daylight saving time) time zone name or abbreviation is output as a string from the environment variable TZ (CDT, for example). If no time zone information exists, no characters are output. The % (percent) character is output. When a modified or unmodified conversion-code is not from the preceding list, the behavior of these functions is undefined. EXAMPLES
The following example uses strftime() to display the current date: #include <time.h> #include <locale.h> #include <stdio.h> #define SLENGTH 80 main() { char nowstr[SLENGTH]; time_t nowbin; const struct tm *nowstruct; (void)setlocale(LC_ALL, ""); if (time(&nowbin) == (time_t) - 1) printf("Could not get time of day from time() "); nowstruct = localtime(&nowbin); if (strftime(nowstr, SLENGTH, "%A %x", nowstruct) == (size_t) 0) printf("Could not get string from strftime() "); printf("Today's date is %s ", nowstr); } NOTES
The %S seconds field can contain a value up to 61 seconds rather than up to 59 seconds to allow leap seconds that are sometimes added to years to keep clocks in correspondence with the solar year. RETURN VALUES
The strftime() function returns the number of bytes written into the array pointed to by the s parameter when the total number of resulting bytes, including the terminating null byte, is not more than the value of the maxsize parameter. The returned value does not count the terminating null byte in the number of bytes written into the array. Otherwise, a value of 0 cast to size_t is returned and the contents of the array are undefined. The wcsftime() function returns the number of wide characters written into the array pointed to by the wcs parameter when the total number of resulting wide characters, including the terminating null wide character, is not more than the value of the maxsize parameter. The returned value does not count the terminating null wide character in the number of wide characters written into the array. Otherwise, a value of 0 cast to size_t is returned and the contents of the array are undefined. RELATED INFORMATION
Functions: ctime(3), mbstowcs(3), setlocale(3), strptime(3) Standards: standards(5) delim off strftime(3)
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