epollpwaitint

epollpwaitint is not a standard Linux system call or API. In official documentation and headers, there is no function named epollpwaitint. The term may be a misspelling or a shorthand combining epoll_pwait with an indication of an integer type or interrupt context. The closest and canonical interface is epoll_pwait.

Epoll is a scalable I/O event notification facility in Linux. It provides mechanism to monitor multiple file descriptors to see if I/O is possible on any of them. Core operations include creating an epoll instance (epoll_create), registering or modifying fds (epoll_ctl), and waiting for events (epoll_wait). A related variant, epoll_pwait, adds the ability to block certain signals while waiting for events, reducing race conditions with signal handlers.

The epoll_pwait function has the prototype: int epoll_pwait(int epfd, struct epoll_event *events, int maxevents, int timeout, const sigset_t *sigmask); The epfd parameter is the epoll instance, events is a buffer to receive ready events, maxevents is its length, timeout specifies the maximum wait time in milliseconds (with -1 meaning wait indefinitely), and sigmask is a pointer to a signal mask that will be temporarily applied during the wait. If sigmask is NULL, the current signal mask remains unchanged. On success, the number of ready file descriptors is returned; 0 can be returned if the timeout expires; on error, -1 is returned and errno is set.

Usage patterns involve creating an epoll instance, registering descriptors with epoll_ctl, and using epoll_pwait when the program needs to control signal handling during the wait. See also epoll_wait, epoll_ctl, and related signal handling facilities like signalfd.