.\" $OpenBSD: pwrite.3,v 1.7 1999/07/09 13:35:25 aaron Exp $
.\" David Leonard <d@openbsd.org>, 1998. Public domain.
.Dd September 7, 1998
.Dt PWRITE 3
.Os
.Sh NAME
.Nm pwrite
.Nd atomic seek and write
.Sh SYNOPSIS
.Fd #include <pthread.h>
.Ft ssize_t
.Fn pwrite "int filedes" "void *buf" "size_t nbytes" "off_t offset"
.Sh DESCRIPTION
The
.Fn pwrite
function writes
.Fa nbyte
bytes from offset
.Fa offset
in the file opened on file descriptor
.Fa filedes.
.Pp
This function is provided for use in a threaded, parallel I/O
environment, where race conditions may exist between two threads
non-atomically seeking and writing to the same file descriptor.
.Sh RETURN VALUES
The
.Fn pwrite
function returns values identical to
.Xr write 2 .
.Sh SEE ALSO
.Xr write 2 ,
.Xr pread 3 ,
.Xr pthreads 3
.Sh STANDARDS
.Fn pwrite
conforms to
.St -susv2 .