+.SH CONFORMING TO
+POSIX.1-2001, POSIX.1-2008.
+.SH NOTES
+The
+.BR pread ()
+and
+.BR pwrite ()
+system calls are especially useful in multithreaded applications.
+They allow multiple threads to perform I/O on the same file descriptor
+without being affected by changes to the file offset by other threads.
+.\"
+.SS C library/kernel differences
+On Linux, the underlying system calls were renamed
+in kernel 2.6:
+.BR pread ()
+became
+.BR pread64 (),
+and
+.BR pwrite ()
+became
+.BR pwrite64 ().
+The system call numbers remained the same.
+The glibc
+.BR pread ()
+and
+.BR pwrite ()
+wrapper functions transparently deal with the change.
+.PP
+On some 32-bit architectures,
+the calling signature for these system calls differ,
+for the reasons described in
+.BR syscall (2).
+.SH BUGS
+POSIX requires that opening a file with the
+.BR O_APPEND
+flag should have no effect on the location at which
+.BR pwrite ()
+writes data.
+However, on Linux, if a file is opened with
+.\" FIXME . https://bugzilla.kernel.org/show_bug.cgi?id=43178
+.BR O_APPEND ,
+.BR pwrite ()
+appends data to the end of the file, regardless of the value of
+.IR offset .
+.SH SEE ALSO