Function read [src]

Queues (but does not submit) an SQE to perform a read(2) or preadv(2) depending on the buffer type. Reading into a ReadBuffer.buffer uses read(2) Reading into a ReadBuffer.iovecs uses preadv(2) If you want to do a preadv2(2) then set rw_flags on the returned SQE. See https://man7.org/linux/man-pages/man2/preadv2.2.html Returns a pointer to the SQE.

Prototype

pub fn read( self: *IoUring, user_data: u64, fd: posix.fd_t, buffer: ReadBuffer, offset: u64, ) !*linux.io_uring_sqe

Parameters

self: *IoUringuser_data: u64fd: posix.fd_tbuffer: ReadBufferoffset: u64

Source

  pub fn read(
    self: *IoUring,
    user_data: u64,
    fd: posix.fd_t,
    buffer: ReadBuffer,
    offset: u64,
) !*linux.io_uring_sqe {
    const sqe = try self.get_sqe();
    switch (buffer) {
        .buffer => |slice| sqe.prep_read(fd, slice, offset),
        .iovecs => |vecs| sqe.prep_readv(fd, vecs, offset),
        .buffer_selection => |selection| {
            sqe.prep_rw(.READ, fd, 0, selection.len, offset);
            sqe.flags |= linux.IOSQE_BUFFER_SELECT;
            sqe.buf_index = selection.group_id;
        },
    }
    sqe.user_data = user_data;
    return sqe;
}  