C date and time functions

The C date and time functions are a group of functions in the standard library of the C programming language implementing date and time manipulation operations. They provide support for time acquisition, conversion between date formats, and formatted output to strings. The C date and time operations are defined in the time.h (ctime header in C++). The and related types were originally proposed by Markus Kuhn to provide a variety of time bases, but only was accepted. The functionalities were, however, added to C++ in 2020 in std::chrono. The following C source code prints the current time to the standard output stream. #include #include #include int main(void) { time_t current_time; char* c_time_string; /* Obtain current time. / current_time = time(NULL); if (current_time == ((time_t)-1)) { (void) fprintf(stderr, "Failure to obtain the current time.\n"); exit(EXIT_FAILURE); } / Convert to local time format. / c_time_string = ctime(&current_time); if (c_time_string == NULL) { (void) fprintf(stderr, "Failure to convert the current time.\n"); exit(EXIT_FAILURE); } / Print to stdout. ctime() has already added a terminating newline character.