C library functions -timespec_get()

C Standard Library - <time.h>

Description

timespec_get()is a function introduced by the C11 standard, used to obtain the current time and store it intimespecstructure. This function provides a way to obtain precise time, typically used for high-resolution timing operations.

Declaration

Below is the declaration of the timespec_get() function.

int timespec_get(struct timespec *ts, int base);

Parameter

  • ts: points totimespecpointer to a structure, which will be filled with the current time.
  • base: time base constant, the C11 standard definesTIME_UTC, representing Coordinated Universal Time (UTC).

Return Value

  • returns on successbasethe value of (usuallyTIME_UTC）。
  • Returns 0 on failure.

struct timespecStructure

struct timespec {
    time_t tv_sec;  // seconds
    long   tv_nsec; // nanoseconds
};

Example

The following example demonstrates the usage of the time() function.

Example

#include <stdio.h> #include <time.h> int main() { struct timespec ts; if (timespec_get(&ts, TIME_UTC) == TIME_UTC) { printf("Current time: %ld seconds and %ld nanoseconds since the Epoch\n", ts.tv_sec, ts.tv_nsec); } else { perror("timespec_get failed"); } return 0; }

Let us compile and run the above program, which will produce the following result:

Current time: 1718332786 seconds and 358463000 nanoseconds since the Epoch

Notes

  • timespec_get()provides more thantime()higher time resolution, because the time it returns includes nanoseconds.
  • Usagetimespec_get()You need to ensure that the code runs in an environment that supports the C11 standard.
  • timespec_get()The main use is high-precision timing, such as measuring code execution time, performance analysis, etc.

related functions

  • clock_gettime(): another function for obtaining high-resolution time, but requires POSIX support.

By understanding and usingtimespec_get(), you can conveniently obtain high-precision current time, thereby writing more efficient and accurate C programs in scenarios that require precise timing.

C Standard Library - <time.h>

other extensions