?? tellwait.c
字號:
#include "apue.h"static volatile sig_atomic_t sigflag; /* set nonzero by sig handler */static sigset_t newmask, oldmask, zeromask;static voidsig_usr(int signo) /* one signal handler for SIGUSR1 and SIGUSR2 */{ sigflag = 1;}voidTELL_WAIT(void){ if (signal(SIGUSR1, sig_usr) == SIG_ERR) err_sys("signal(SIGUSR1) error"); if (signal(SIGUSR2, sig_usr) == SIG_ERR) err_sys("signal(SIGUSR2) error"); sigemptyset(&zeromask); sigemptyset(&newmask); sigaddset(&newmask, SIGUSR1); sigaddset(&newmask, SIGUSR2); /* * Block SIGUSR1 and SIGUSR2, and save current signal mask. */ if (sigprocmask(SIG_BLOCK, &newmask, &oldmask) < 0) err_sys("SIG_BLOCK error");}voidTELL_PARENT(pid_t pid){ kill(pid, SIGUSR2); /* tell parent we're done */}voidWAIT_PARENT(void){ while (sigflag == 0) sigsuspend(&zeromask); /* and wait for parent */ sigflag = 0; /* * Reset signal mask to original value. */ if (sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0) err_sys("SIG_SETMASK error");}voidTELL_CHILD(pid_t pid){ kill(pid, SIGUSR1); /* tell child we're done */}voidWAIT_CHILD(void){ while (sigflag == 0) sigsuspend(&zeromask); /* and wait for child */ sigflag = 0; /* * Reset signal mask to original value. */ if (sigprocmask(SIG_SETMASK, &oldmask, NULL) < 0) err_sys("SIG_SETMASK error");}
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