how much cpu time used by your application

// 1 Make the includes for all the functions we're going to be using in this program.
**link with -lm

#include
#include
#include
#include
#include

// 2 The void function writes a string to a temporary file 10000 times and then performs some arithmetic
// to generate load on the CPU.

void work()
{
FILE *f;
int i;
double x = 4.5;

f = tmpfile();
for(i = 0; i < 10000; i++) {
fprintf(f,"Do some output\n");
if(ferror(f)) {
fprintf(stderr,"Error writing to temporary file\n");
exit(1);
}
}
for(i = 0; i < 1000000; i++)
x = log(x*x + 3.21);
}

// 3 The main function calls work and then uses the getrusage function to discover how much CPU time it has used. It displays this information on screen.

int main()
{
struct rusage r_usage;
struct rlimit r_limit;
int priority;

work();
getrusage(RUSAGE_SELF, &r_usage);

printf("CPU usage: User = %ld.%06ld, System = %ld.%06ld\n",
r_usage.ru_utime.tv_sec, r_usage.ru_utime.tv_usec,
r_usage.ru_stime.tv_sec, r_usage.ru_stime.tv_usec);

// 4 Next, it calls getpriority and getrlimit to find out its current priority and file size limits respectively.

priority = getpriority(PRIO_PROCESS, getpid());
printf("Current priority = %d\n", priority);

getrlimit(RLIMIT_FSIZE, &r_limit);
printf("Current FSIZE limit: soft = %ld, hard = %ld\n",
r_limit.rlim_cur, r_limit.rlim_max);

// 5 Finally, we set a file size limit using setrlimit and call work again, which fails because
// it attempts to create too large a file.

r_limit.rlim_cur = 2048;
r_limit.rlim_max = 4096;
printf("Setting a 2K file size limit\n");
setrlimit(RLIMIT_FSIZE, &r_limit);

work();
exit(0);
}