A C programming language example

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The following C program contains two instrumented sections which perform a trivial floating point operation, print the results, and then launch the command interpreter to execute the ls -R / 2>&1 >/dev/null command.

#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <libhpm.h>

void
do_work()
{
        pid_t p, wpid;
        int i, status;
        float f1 = 9.7641, f2 = 2.441, f3 = 0.0;

        f3 = f1 / f2;
        printf("f3=%f\n", f3);

        p = fork();

        if (p == -1) {
          perror("Mike fork error");
          exit(1);
        }

        if (p == 0) {
          i = execl("/usr/bin/sh", "sh", "-c", "ls -R / 2>&1 >/dev/null", 0);
          perror("Mike execl error");
          exit(2);
        }
        else
          wpid = waitpid(p, &status, WUNTRACED | WCONTINUED);

        if (wpid == -1) {
            perror("Mike waitpid error");
            exit(3);
        }

        return;
}

main(int argc, char **argv)
{
        int taskID = 999;

        hpmInit(taskID, "my_program");
        hpmStart(1, "outer call");
        do_work();
        hpmStart(2, "inner call");
        do_work();
        hpmStop(2);
        hpmStop(1);
        hpmTerminate(taskID);
}