need c programming help?

Question

i have to calculate the time difference in microsoconds for a particular operation, say for calling a function, how do i do with.
it is better if you list some functions related to this

Answer 1

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Answer 2

FOR UNIX ONLY::::::::::
SYNOPSIS
#include
int gettimeofday(struct timeval *restrict tp, void *restrict tzp);
DESCRIPTION

The gettimeofday() function shall obtain the current time, expressed as seconds and microseconds since the Epoch, and store it in the timeval structure pointed to by tp. The resolution of the system clock is unspecified.

If tzp is not a null pointer, the behavior is unspecified.

Answer 3

in time.h, that functions r defined. go and get knw abt those function.

Return number of clock ticks since process start.
Returns the number of clock ticks elapsed.
A macro constant called CLK_TCK defines the relation betwen clock tick and second (clock ticks per second).

Parameters.

(none)
Return Value.
The number of clock ticks elapsed since start.
clock_t type is defined by default as long int by most compilers.

Portability.
Defined in ANSI-C.


Example.


/* clock example: countdown */
#include
#include

void wait ( int seconds )
{
clock_t endwait;
endwait = clock () + seconds * CLK_TCK ;
while (clock() < endwait) {}
}

int main ()
{
int n;
printf ("Starting countdown...\n");
for (n=10; n>0; n--)
{
printf ("%d\n",n);
wait (1);
}
printf ("FIRE!!!\n");
return 0;
}

Answer 4

I doubt if you can do it in microseconds. Till my information, only in kernel level you can do at microsecond level. In application level only available is upto seconds.