.Dd February 13, 2020
.Dt XREAD 3
.Os
.\"
.Sh NAME
.Nm xread ,
.Nm xpread
.Nd read bytes from a file descriptor handling partial reads internally
.\"
.Sh SYNOPSIS
.In jeffpc/io.h
.Ft int
.Fn xread "int fd" "void *buf" "size_t nbyte"
.Ft int
.Fn xpread "int fd" "void *buf" "size_t nbyte" "off_t off"
.\"
.Sh DESCRIPTION
The
.Fn xread
and
.Fn xpread
functions attempt to read
.Fa nbyte
bytes from the file descriptor specified by the
.Fa fd
argument.
The read data is stored in the first
.Fa nbyte
bytes pointed to by
.Fa buf .
.sp
.Fn xpread
reads from the current position of the file descriptor and updates it in the
same manner as
.Xr read 2 .
.sp
.Fn xpread
reads from the file offset specified by
.Fa off
leaving the file descriptor's current position unchanged in the same manner
as
.Xr pread 2 .
.\"
.Sh RETURN VALUES
On success
.Fn xread
and
.Fn xpread
return 0, and a negated errno otherwise.
.\"
.Sh ERRORS
Both
.Fn xread
and
.Fn xpread
forward any errors from
.Xr read 2
and
.Xr pread 2 ,
respectively with the following differences:
.Bl -tag -width Er
.It Er -EPIPE
The requested number of bytes could not be read.
If
.Fn xread
was used, the file descriptor's new position may be anywhere between the
original location and
.Fa nbyte
bytes following it.
.El
.\"
.Sh SEE ALSO
.Xr pread 2 ,
.Xr read 2