Time stamp function obtained under Unix/linux system

Under the Unix/linux system, the Gettimeofday function is used to obtain the timestamp of the current system, which can reach a microsecond (microsecond, or μs) level.

The information for the current timestamp is stored through the struct Timeval:

#ifndef _struct_timeval #define _struct_timeval        STRUCT timeval_struct_timeval{    __darwin_time_t         tv_sec;          /*  */    __darwin_suseconds_t    tv_usec        ; /* */}; #endif /* _struct_timeval */

Where tv_sec is used to hold the current timestamp of the number of seconds, generally a long type, tv_usec is used to hold the current timestamp of the number of microseconds, generally int type.

This structure and the Gettimeofday function are declared in the <sys/time.h> header file.

Here's an example:

#include <sys/time.h>intMainvoid){        structtimeval Tbegin, tEnd; Gettimeofday (&Tbegin, NULL); intCount =0;  for(inti =0; I < +* +; i++) Count+=i; Gettimeofday (&tEnd, NULL); LongDeltatime =1000000L* (TEND.TV_SEC-TBEGIN.TV_SEC) + (Tend.tv_usec-tbegin.tv_usec); printf ("Time spent:%ldus\n", deltatime);}

In the preceding code, gettimeofday (&tbegin, NULL) is used to obtain the timestamp before the calculation, while gettimeofday (&tend, NULL) is used to obtain the timestamp after the calculation. Then deltatime can get the number of microseconds between two timestamps. Finally, the result is output.

Time stamp function obtained under Unix/linux system