epoll_create1 - Linux


The epoll_create1 command in Linux creates an epoll instance, which is a data structure used for efficient, event-based I/O processing. It is used for monitoring file descriptors, sockets, and similar resources for events like data availability or connection changes.


int epoll_create1(int flags);


  • EPOLL_CLOEXEC: Sets the close-on-exec flag on the new file descriptor.


Create a basic epoll instance:

int epollfd = epoll_create1(0);

Create an epoll instance with the close-on-exec flag:

int epollfd = epoll_create1(EPOLL_CLOEXEC);

Common Issues

  • Using epoll_create1 without appropriate error handling can lead to errors if the creation fails.
  • Mixing epoll_create1 with other epoll functions like epoll_ctl or epoll_wait from different epoll implementations can cause inconsistent behavior.


epoll_create1 is commonly used with other Linux commands and tools for asynchronous I/O processing. For example, it can be combined with:

  • epoll_ctl: To add or modify file descriptors in the epoll instance.
  • epoll_wait: To wait for events on the registered file descriptors.
  • select: For a more traditional I/O event monitoring approach.

Related Commands

  • epoll_ctl: Controls (adds, modifies, or deletes) file descriptors in an epoll instance.
  • epoll_wait: Waits for events on a set of file descriptors in an epoll instance.
  • poll: Another function for event-based I/O monitoring.