posix_timers.h

/*
 * An example of how to use signals to implement a timer facility using 
 * POSIX threads.
 *
 * Rationale: when using normal Unix signals (SIGALRM), the signal handler executes
 * in a signal handler context.  In a signal handler context, only async-signal-safe
 * functions may be called.  Few POSIX functions are async-signal-safe.
 *
 * Instead of handling the timer activity in the signal handler function,
 * we create a separate thread to perform the timer activity.
 * This timer thread receives a signal from a semaphore, which is signaled ("posted")
 * every time a timer signal arrives.
 *
 * You'll have to redefine "timer_func" below and "set_periodic_timer."
 *
 * Read the man pages of the functions used, such as signal(2), signal(7),
 * alarm(2).
 *
 * Written by Godmar Back <gback@cs.vt.edu>, February 2006.
 */

#ifndef __POSIXTIMERS
#define __POSIXTIMERS

/**
 * NOTE: the user has to provide a function with the signature:

         void timer_func(void); 
 */

void init_timer(void);
void shutdown_timer();
void set_periodic_timer(long delay);

#endif