Ammar Faizi <ammarfaizi2@xxxxxxxxxxx> writes: > From: Ammar Faizi <ammarfaizi2@xxxxxxxxxxx> > > I have found two people confused about the io_uring_prep_splice() > function, especially on the offset part. The current manpage for > io_uring_prep_splice() doesn't tell about the rules of the offset > arguments. > > Despite these rules are already noted in "man 2 io_uring_enter", > people who want to know about this prep function will prefer to read > "man 3 io_uring_prep_splice". > > Let's explain it there! Hi Ammar, A few suggestions below: > --- a/man/io_uring_prep_splice.3 > +++ b/man/io_uring_prep_splice.3 > @@ -52,6 +52,34 @@ and > .I fd_in > given as a registered file descriptor offset. > > +If > +.I fd_in > +refers to a pipe, > +.IR off_in > +must be -1. Maybe "off_in is ignored and must be set to -1." > + > +If > +.I fd_in > +does not refer to a pipe and > +.I off_in > +is -1, then bytes are read from bytes -> nbytes ? > +.I fd_in > +starting from the file offset and it is adjusted appropriately. What do you think: starting from the file offset, which is incremented by the number of bytes read. > +If > +.I fd_in > +does not refer to a pipe and > +.I off_in > +is not -1, then the starting offset of > +.I fd_in > +will be > +.IR off_in . > + > +The same rules apply to > +.I fd_out > +and > +.IR off_out . > + > This function prepares an async > .BR splice (2) > request. See that man page for details. > @@ -78,3 +106,13 @@ field. > .BR io_uring_submit (3), > .BR io_uring_register (2), > .BR splice (2) > + > +.SH NOTES > +Note that even if > +.I fd_in > +or > +.I fd_out > +refers to a pipe, the splice operation can still failed with failed -> fail Thanks, -- Gabriel Krisman Bertazi
