pid_t pid;

pid = fork();

if(pid < 0) {
    // error condition, check errno
}
else if(pid == 0) {
    // This is the child, so invoke a call to the library to see if it works
}
else {
    // This is the parent, unless you wish to wait for the child to complete, nothing to be done here
    // you can of course validate here, or above the call to fork() to verify that the parent can call library
    // functions.  A helpful call would be waitpid(2), declare int w_status as a variable.
    waitpid(pid, &w_status, 0);
    // This would wait for the child to terminate and then you can invoke test macros against w_status.
    // see "man -S 2 waitpid for information on the various macros you can use to test the outcome of your child.
}