#include <sys/types.h> #include <sys/socket.h> #include <liburing.h> void io_uring_prep_connect(struct io_uring_sqe *sqe, int sockfd, const struct sockaddr *addr, socklen_t addrlen);
The io_uring_prep_connect(3) function prepares a connect request. The submission queue entry sqe is setup to use the file descriptor sockfd to start connecting to the destination described by the socket address at addr and of structure length addrlen.
This function prepares an async connect(2) request. See that man page for details.
The CQE res field will contain the result of the operation. See the related man page for details on possible values. Note that where synchronous system calls will return -1 on failure and set errno to the actual error value, io_uring never uses errno. Instead it returns the negated errno directly in the CQE res field.
As with any request that passes in data in a struct, that data must remain valid until the request has been successfully submitted. It need not remain valid until completion. Once a request has been submitted, the in-kernel state is stable. Very early kernels (5.4 and earlier) required state to be stable until the completion occurred. Applications can test for this behavior by inspecting the IORING_FEAT_SUBMIT_STABLE flag passed back from io_uring_queue_init_params(3).
io_uring_get_sqe(3), io_uring_submit(3), connect(2)