Syntax
#include <time.h>
size_t strftime(char *dest, size_t maxsize,
const char *format, const struct tm *timeptr);
Description
strftime converts the time and date specification in the timeptr structure into a character string. It then stores the null-terminated string in the array pointed to by dest according to the format string pointed to by format. maxsize specifies the maximum number of bytes that can be copied into the array.
The format string is a multibyte character string containing:
If data has the form of a conversion specifier, but is not one of the accepted specifiers, the characters following the % are copied to the output.
The characters that are converted are determined by the LC_TIME category of the current locale and by the values in the time structure pointed to by timeptr. The time structure pointed to by timeptr is usually obtained by calling the gmtime or localtime function.
When objects to be copied overlap, the behavior is undefined.
The following table lists the strftime conversion specifiers: ┌──────────┬──────────────────────────────────────────────────────┐│Specifier
│Meaning │
├──────────┼──────────────────────────────────────────────────────┤
│ %a │ Replace with abbreviated weekday name from locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %A │ Replace with full weekday name from locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %b │ Replace with abbreviated month name from locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %B │ Replace with full month name from locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %c │ Replace with date and time from locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %C │ Replace with locale's century number (year divided │
│ │ by 100 and truncated) │
├──────────┼──────────────────────────────────────────────────────┤
│ %d │ Replace with day of the month as a decimal number │
│ │ (01-31). │
├──────────┼──────────────────────────────────────────────────────┤
│ %D │ Insert date in mm/dd/yy form, regardless of locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %e │ Insert day of the month as a decimal number │
│ │ (" 1"-"31"). A space precedes a single digit. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Ec │ Replace with the locale's alternative date and time │
│ │ representation. │
├──────────┼──────────────────────────────────────────────────────┤
│ %EC │ Replace with the name of the base year (period) in │
│ │ the locale's alternate representation. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Ex │ Replace with the locale's alternative date represen- │
│ │ tation. │
├──────────┼──────────────────────────────────────────────────────┤
│ %EX │ Replace with the locale's alternative time represen- │
│ │ tation. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Ey │ Replace with the offset from %EC (year only) in the │
│ │ locale's alternate representation. │
├──────────┼──────────────────────────────────────────────────────┤
│ %EY │ Replace with the full alternative year represen- │
│ │ tation. │
├──────────┼──────────────────────────────────────────────────────┤
│ %h │ Replace with locale's abbreviated month name. This │
│ │ is the same as %b. │
├──────────┼──────────────────────────────────────────────────────┤
│ %H │ Replace with hour (24-hour clock) as a decimal │
│ │ number (00-23). │
├──────────┼──────────────────────────────────────────────────────┤
│ %I │ Replace with hour (12-hour clock) as a decimal │
│ │ number (01-12). │
├──────────┼──────────────────────────────────────────────────────┤
│ %j │ Replace with day of the year as a decimal number │
│ │ (001-366). │
├──────────┼──────────────────────────────────────────────────────┤
│ %m │ Replace with month as a decimal number (01-12). │
├──────────┼──────────────────────────────────────────────────────┤
│ %M │ Replace with minute as a decimal number (00-59). │
├──────────┼──────────────────────────────────────────────────────┤
│ %n │ Replace with a newline character. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Od │ Replace with the day of month, using the locale's │
│ │ alternative numeric symbols, filled as needed with │
│ │ leading zeroes if there is any alternative symbol │
│ │ for zero; otherwise fill with leading spaces. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Oe │ Replace with the day of the month, using the │
│ │ locale's alternative numeric symbols, filled as │
│ │ needed with leading spaces. │
├──────────┼──────────────────────────────────────────────────────┤
│ %OH │ Replace with the hour (24-hour clock), using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %OI │ Replace with the hour (12-hour clock), using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Om │ Replace with the month, using the locale's alterna- │
│ │ tive numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %OM │ Replace with the minutes, using the locale's alter- │
│ │ native numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %OS │ Replace with the seconds, using the locale's alter- │
│ │ native numeric symbols. │
└──────────┴──────────────────────────────────────────────────────┘
┌──────────┬──────────────────────────────────────────────────────┐
│ %Ou │ Replace with the weekday as a decimal number (1 to │
│ │ 7), with 1 representing Monday, using the locale's │
│ │ alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %OU │ Replace with the week number of the year (00-53), │
│ │ where Sunday is the first day of the week, using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ &OV │ Replace with week number of the year (01-53), where │
│ │ Sunday is the first day of the week, using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Ow │ Replace with the weekday (Sunday=0), using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ % OW │ Replace with the week number of the
year (01-53), │
│ │ where Monday is the first day of the week, using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Oy │ Replace with the year (offset from %C) in the │
│ │ locale's alternative representation, using the │
│ │ locale's alternative numeric symbols. │
├──────────┼──────────────────────────────────────────────────────┤
│ %p │ Replace with the locale's equivalent of AM or PM. │
├──────────┼──────────────────────────────────────────────────────┤
│ %r │ Replace with a string equivalent to %I:%M:%S %p. │
├──────────┼──────────────────────────────────────────────────────┤
│ %R │ Replace with time in 24 hour notation (%H:%M) │
├──────────┼──────────────────────────────────────────────────────┤
│ %S │ Replace with second as a decimal number (00-61). │
├──────────┼──────────────────────────────────────────────────────┤
│ %t │ Replace with a tab. │
├──────────┼──────────────────────────────────────────────────────┤
│ %T │ Replace with a string equivalent to %H:%M:%S. │
├──────────┼──────────────────────────────────────────────────────┤
│ %u │ Replace with the weekday as a decimal number (1 to │
│ │ 7), with 1 representing Monday. │
├──────────┼──────────────────────────────────────────────────────┤
│ %U │ Replace with week number of the year (00-53), where │
│ │ Sunday is the first day of the week. │
├──────────┼──────────────────────────────────────────────────────┤
│ %V │ Replace with week number of the year (01-53), where │
│ │ Monday is the first day of the week. If the week of │
│ │ January 1 is four or more days in the new year, it │
│ │ is week 1; otherwise, it is week 53 of the previous │
│ │ year and the following week is week 1. │
├──────────┼──────────────────────────────────────────────────────┤
│ %w │ Replace with weekday (0-6), where Sunday is 0. │
├──────────┼──────────────────────────────────────────────────────┤
│ %W │ Replace with week number of the year (00-53), where │
│ │ Monday is the first day of the week. │
├──────────┼──────────────────────────────────────────────────────┤
│ %x │ Replace with date representation of locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %X │ Replace with time representation of locale. │
├──────────┼──────────────────────────────────────────────────────┤
│ %y │ Replace with year without the century as a decimal │
│ │ number (00-99). │
├──────────┼──────────────────────────────────────────────────────┤
│ %Y │ Replace with year including the century as a decimal │
│ │ number. │
├──────────┼──────────────────────────────────────────────────────┤
│ %Z │ Replace with name of time zone, or no characters if │
│ │ time zone is not available. │
├──────────┼──────────────────────────────────────────────────────┤
│ %% │ Replace with %. │
└──────────┴──────────────────────────────────────────────────────┘
For %Z, the tm_isdst flag in the tm structure passed to strftime specifies whether the time zone is standard or Daylight Savings time.
If data has the form of a directive, but is not one of the above, the characters following the % are copied to the output.
If the total number of bytes in the resulting string including the terminating null byte does not exceed maxsize, strftime returns the number of bytes placed into dest, not including the terminating null byte; otherwise, strftime returns 0 and the content of the string is indeterminate.
This example gets the time and date from localtime, calls strftime to format it, and prints the resulting string.
#include <stdio.h>
#include <time.h>
int main(void)
{
char dest[70];
int ch;
time_t temp;
struct tm *timeptr;
temp = time(NULL);
timeptr = localtime(&temp);
ch = strftime(dest, sizeof(dest)-1, "Today is %A,"" %b %d. \n Time: %I:%M %p"
, timeptr);
printf("%d characters placed in string to make: \n \n %s", ch, dest);
return 0;
/****************************************************************************
The output should be similar to:
41 characters placed in string to make:
Today is Monday, Sep 16.
Time: 06:31 pm
****************************************************************************/
}
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