NAME

       io_uring_prep_write - prepare I/O write request

SYNOPSIS

       #include <liburing.h>

       void io_uring_prep_write(struct io_uring_sqe *sqe,
                                int fd,
                                const void *buf,
                                unsigned nbytes,
                                __u64 offset);

DESCRIPTION

       The io_uring_prep_write(3) prepares an IO write request. The submission queue entry sqe is
       setup to use the file descriptor fd to start writing nbytes from the  buffer  buf  at  the
       specified offset.

       On  files  that support seeking, if the offset is set to -1, the write operation commences
       at the file offset, and the file offset is incremented by the number of bytes written. See
       write(2)  for  more  details. Note that for an async API, reading and updating the current
       file offset may result in unpredictable behavior, unless access to the file is serialized.
       It is not encouraged to use this feature if it's possible to provide the desired IO offset
       from the application or library.

       On files that are not capable of seeking, the offset is ignored.

       After the write has been prepared, it can be submitted with one of the submit functions.

RETURN VALUE

       None

ERRORS

       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.

SEE ALSO

       io_uring_get_sqe(3), io_uring_submit(3)