Is there a way to find out the errno
when epoll_wait
returns EPOLLERR
for a particular fd?
Is there any further information about the nature of the error?
Edit:
Adding more information to prevent ambiguity
epoll_wait
waits on a number of file descriptors. When you call epoll_wait
you pass it an array of epoll_event
structures:
struct epoll_event { uint32_t events; /* Epoll events */ epoll_data_t data; /* User data variable */ };
The epoll_data_t
structure has the same details as the one you used with epoll_ctl
to add a file descriptor to epoll:
typedef union epoll_data { void *ptr; int fd; uint32_t u32; uint64_t u64; } epoll_data_t;
What I’m looking for is what happens when there is an error on one of the file descriptors that epoll is waiting on.
ie: (epoll_event.events & EPOLLERR) == 1
– is there a way to find out more details of the error on the file descriptor?
Advertisement
Answer
Use getsockopt and SO_ERROR to get the pending error on the socket
int error = 0; socklen_t errlen = sizeof(error); if (getsockopt(fd, SOL_SOCKET, SO_ERROR, (void *)&error, &errlen) == 0) { printf("error = %sn", strerror(error)); }