The difference between sigsuspend and sigwait

sigsuspend(const sigset_t *mask)

Set the blocking signal to mask, Wait for other signals （ except mask Other signals ） Happen , If the signal occurs and the corresponding handler Has been carried out , Then return to -1, And set the corresponding errno( The value of the signal that has occurred ）.

Be careful ：sigsuspend Always returns -1
When the program is executed to suspend Signals that have occurred before will not be sigsuspend Capture
sigsuspend Call to change the signal mask state of the process , Blocking mask Signal in , When the call returns, change the mask to the state before the call


sigwait(const sigset_t *mask, int *sig):

wait for mask Signal in （ Any one can ） happen , If it happens , Set up *sig For signals that have occurred , return 0. If there is an error, return -1.

Be careful ：sigwait Don't wait hander The signal of execution is equivalent to being sigwait to intercept ,handler It will not be called to execute .
sigwait Automatically cancel when calling mask Signal mask status in , Until a new signal arrives , Recover the signal mask word of the thread on return .

sigwait Call to
Wait for a signal to occur