ref: 0f595fa896765dfdbe88c760ebd97edd8a1f123b
dir: /doc/man3/time.h.3/
.TH time.h 3 .SH NAME time.h - time types .SH SYNOPSIS #include <time.h> The time.h header declares the following functions: .nf char asctime(const struct tm *tm); clock_t clock(void); char ctime(const time_t *timep); double difftime(time_t t1, time_t t2); struct tm *gmtime(const time_t *timep); struct tm *localtime(const time_t *timep); time_t mktime(struct tm *tm); size_t strftime(char *restrict, size_t, const char *restrict, const struct tm *restrict); time_t time(time_t *timer); .fi .SH DESCRIPTION The time.h header defines the following macros: .B NULL It expands to an implementation-defined null pointer constant, as defined in stddef.h header. .B CLOCKS_PER_SEC A number used to convert the value returned by the .BR clock () function into seconds. The value is an expression with type clock_t. The time.h header defines the following types: .BR clock_t , .BR size_t , .BR time_t . The time.h header declares the .B tm structure, which includes at least the following members: .nf int tm_sec Seconds[0,60] int tm_min Minutes[0,59] int tm_hour Hour[0,23] int tm_mday Day of month [1,31] int tm_mon Month of year [0,11] int tm_year Years since 1900 int tm_wday Day of week [0,6] (Sunday =0) int tm_yday Day of year [0,365] int tm_isdst Daylight Savings flag .fi The members of the .I tm structure are: .TP 10 tm_sec The number of seconds after the minute, normally in the range 0 to 59, but can be up to 60 to allow for leap seconds. .TP tm_min The number of minutes after the hour, in the range 0 to 59. .TP tm_hour The number of hours past midnight, in the range 0 to 23. .TP tm_mday The day of the month, in the range 1 to 31. .TP tm_mon The number of months since January, in the range 0 to 11. .TP tm_year The number of years since 1900. .TP tm_wday The number of days since Sunday, in the range 0 to 6. .TP tm_yday The number of days since January 1, in the range 0 to 365. .TP tm_isdst A flag that indicates whether daylight saving time is in effect at the time described. The value is positive if daylight saving time is in effect, zero if it is not, and negative if the information is not available. .SH STANDARDS ISO/IEC 9899:1999 Section 7.23.1 Paragraph 1,2,3,4 .SH SEE ALSO .BR clock (3) .BR ctime (3) .BR difftime (3) .BR strftime (3) .BR time (3)