synchro.cpp

这是一个linux下的Shell.有命令历史和命令提示

#include "synchro.h"
static volatile sig_atomic_t sigflag;
static bool synchronismFlag = true;
static sigset_t newmask, oldmask, zeromask;
static void sig_usr(int signo);

static void sig_usr(int signo)
{
	sigflag = 1;
	return;
}

void TELL_WAIT(void)
{
	if(signal(SIGUSR1, sig_usr) == SIG_ERR)
		synchronismFlag = false;
	if(signal(SIGUSR2, sig_usr) == SIG_ERR)
		synchronismFlag = false;
	sigemptyset(&zeromask);
	
	sigemptyset(&newmask);
	sigaddset(&newmask, SIGUSR1);
	sigaddset(&newmask, SIGUSR2);
	if(sigprocmask(SIG_BLOCK, &newmask, &oldmask) < 0)
		synchronismFlag = false;
}

void TELL_PARENT(pid_t pid)
{
	kill(pid, SIGUSR2);
}

void WAIT_PARENT(void)
{
	while(sigflag == 0)
		sigsuspend(&zeromask);
	sigflag = 0;

	if(sigprocmask(SIG_SETMASK, &oldmask, 0) < 0)
		synchronismFlag = false;
}
void TELL_CHILD(pid_t pid)
{
	kill(pid, SIGUSR1);
}

void WAIT_CHILD(void)
{
	while(sigflag == 0)
		sigsuspend(&zeromask);
	
	sigflag = 0;
	if(sigprocmask(SIG_SETMASK, &oldmask, 0) < 0)
		synchronismFlag = false;
}

bool isSynchroAble(void)
{
	return synchronismFlag;
}