@node difftime, time
@findex difftime
@subheading Syntax

@example
#include <time.h>

double difftime(time_t t1, time_t t0);
@end example

@subheading Description

This function returns the difference in time, in seconds, from @var{t0}
to @var{t1}. 

@subheading Return Value

The number of seconds.

@subheading Portability

@portability ansi, posix

@subheading Example

@example
time_t t1, t0;
double elapsed;
time(&t0);
do_something();
time(&t1);
elapsed = difftime(t1, t0);
@end example