C++ Standard Library C++ STL Library

C++ - <ctime> (time.h)



The C++ <ctime> header defines several functions, types and macros to get and manipulate date and time information. These types and macros are available to use in a current program after including the header file using - #include <ctime> or #include <time.h>. All types and macros of this header file are listed below:

Library Functions

Time manipulation functions

FunctionsDescription
clock() Returns raw processor clock time since the program is started.
difftime() Returns difference between two times.
mktime() Converts tm structure to time_t.
time() Returns the current time.

Format conversion functions

FunctionsDescription
asctime() Converts tm structure to a textual representation.
ctime() Converts time_t value to a textual representation.
gmtime() Converts time_t value into calendar time, expressed in UTC time.
localtime() Converts time_t value into calendar time, expressed in local time.
strftime() Formats time as string.

Library Types

TypesDescription
clock_t Process running time.
size_t Unsigned integer type.
time_t Time type.
tm Time structure.

Library Macros

Macro constants

MacrosDescription
CLOCKS_PER_SEC Number of processor clock ticks per second.
NULL Null pointer.