io_uring_prep_waitid(3) liburing Manual io_uring_prep_waitid(3)

io_uring_prep_waitid - prepare a waitid request

#include <sys/wait.h>
#include <liburing.h>
void io_uring_prep_waitid(struct io_uring_sqe *sqe,
                          idtype_t idtype,
                          id_t id,
                          siginfo_t *infop,
                          int options,
                          unsigned int flags);

The io_uring_prep_waitid(3) function prepares a waitid request. The submission queue entry sqe is setup to use the idtype and id arguments select the child(ren), and options to specify the child state changes to wait for. Upon successful return, it fills infop with information of the child process, if any. flags is io_uring specific modifier flags. They are currently unused, and hence 0 should be passed.

This function prepares an async waitid(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.

io_uring_get_sqe(3), io_uring_submit(3), waitid(2)

July 14, 2023 liburing-2.5