A/UX® Programmer's Reference

intro(2) intro(2)
NAME
intro - introduction to system calls and error numbers
SYNOPSIS
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DESCRIPTION
This section describes all of the AjUX® system calls. The system
calls identified with the letter "P" following the section number
are part of the NUX POSIX environment. The NUX POSIX
programming environment is described in the AIUX Guide to PO­
SIX and A/UX Programming Languages and Tools, Volume 1.
Most of these calls have one or more error returns. An error condition
is indicated by a returned value that is otherwise impossible,
which is almost always -1. The individual descriptions specify
the details. An error number is also made available in the external
variable errno, which is not cleared on successful calls. So
errno, should be tested only after an error has been indicated.
There is a table of messages associated with each error and a routine
for printing the message (see perror(3C). Each systemcall
description attempts to list all possible error numbers.
ERRORS
The following is a complete list of AjUX error numbers and their
names as defined in . Also given is a description of
the most likely cause of the error.
1 EPERM Not owner
Typically this error indicates an attempt to modify a file in
some way forbidden except to its owner or the superuser. It
is also returned when ordinary users attempt modifications
reserved for the superuser.
2 ENOENT No such file or directory
This error occurs when a filename is specified and the file
should exist but doesn't, or when one of the directories in a
path name does not exist.
3 ESRCH No such process
No process can be found corresponding to that specified by
pid in kill or ptrace.
4 EINTR Interrupted system call
An asynchronous signal, such as an interrupt or quit, which
the user program elected to catch, occurred during a system
call. If execution is resumed after processing the signal, it
February, 1990
Revision C
1