get the current time of a clock
#include <time.h>
int clock_gettime( clockid_t clock_id,
struct timespec *tp );
The clock_gettime() function gets the current time of the clock specified by clock_id, and puts it into the buffer pointed to by tp. The only supported clock ID is CLOCK_REALTIME.
The tp parameter points to a structure containing at least the following members:
- time_t tv_sec
- The number of seconds since 1970.
- time_t tv_nsec
- The number of nanoseconds expired in the current second. This value increases by some multiple of nanoseconds, based on the system clock's resolution.
- 0
- Success
- -1
- An error occurred. errno is set to indicate the error.
- EINVAL
- The clock_id is not CLOCK_REALTIME.
/*
* This program calculates the time required to
* execute the program specified as its first argument.
* The time is printed in seconds, on standard out.
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>
#define BILLION 1000000000L;
int main( int argc, char **argv )
{
struct timespec start, stop;
double accum;
if( clock_gettime( CLOCK_REALTIME, &start) == -1 ) {
perror( "clock gettime" );
exit( EXIT_FAILURE );
}
system( argv[1] );
if( clock_gettime( CLOCK_REALTIME, &stop) == -1 ) {
perror( "clock gettime" );
exit( EXIT_FAILURE );
}
accum = ( stop.tv_sec - start.tv_sec )
+ ( stop.tv_nsec - start.tv_nsec )
/ BILLION;
printf( "%lf\n", accum );
return( EXIT_SUCCESS );
int64_t getUniqId() {
timeb tb;
ftime( &tb );
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
int64_t uniqId = tb.millitm + (tb.time * 1000) + (ts.tv_nsec * 1000000000);
return uniqId;
}