194 Chapter 10
Listing 10-2: A function that returns a string containing the current time
–––––––––––––––––––––––––––––––––––––––––––––––––––––––––– time/curr_time.c
#include <time.h>
#include "curr_time.h" /* Declares function defined here */#define BUF_SIZE 1000/* Return a string containing the current time formatted according to
the specification in 'format' (see strftime(3) for specifiers).
If 'format' is NULL, we use "%c" as a specifier (which gives the
date and time as for ctime(3), but without the trailing newline).
Returns NULL on error. */Table 10-1: Selected conversion specifiers for strftime()Specifier Description Example
%% A % character %
%a Abbreviated weekday name Tue
%A Full weekday name Tuesday
%b, %h Abbreviated month name Feb
%B Full month name February
%c Date and time Tue Feb 1 21:39:46 2011
%d Day of month (2 digits, 01 to 31) 01
%D American date (same as %m/%d/%y) 02/01/11
%e Day of month (2 characters) 1
%F ISO date (same as %Y-%m-%d) 2011-02-01
%H Hour (24-hour clock, 2 digits) 21
%I Hour (12-hour clock, 2 digits) 09
%j Day of year (3 digits, 001 to 366) 032
%m Decimal month (2 digits, 01 to 12) 02
%M Minute (2 digits) 39
%p AM/PM PM
%P am/pm (GNU extension) pm
%R 24-hour time (same as %H:%M) 21:39
%S Second (00 to 60) 46
%T Time (same as %H:%M:%S) 21:39:46
%u Weekday number (1 to 7, Monday = 1) 2
%U Sunday week number (00 to 53) 05
%w Weekday number (0 to 6, Sunday = 0) 2
%W Monday week number (00 to 53) 05
%x Date (localized) 02/01/11
%X Time (localized) 21:39:46
%y 2-digit year 11
%Y 4-digit year 2011
%Z Timezone name CET