sysexits.h.3head: Move header page to a new man3head section

Use man3head, as other Unix systems already use.
As Ingo said, man0 is not the right place for header files.

Also, this patch does some changes to the page itself:

Expand the SYNOPSIS to have together all of the values.  Also, add
a small comment about the constant (taken from the header file).

Link: <https://lore.kernel.org/linux-man/11110a04-f96b-0d32-53e3-adcce618c543@gmail.com/>
Cc: "G. Branden Robinson" <g.branden.robinson@gmail.com>
Cc: Ingo Schwarze <schwarze@openbsd.org>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>

1 files changed, 196 insertions, 0 deletions

diff --git a/man3head/sysexits.h.3head b/man3head/sysexits.h.3head
new file mode 100644
index 000000000..47ad32a51
--- /dev/null
+++ b/man3head/sysexits.h.3head
@@ -0,0 +1,196 @@
+.\" Copyright (c) 1996 Joerg Wunsch
+.\" Copyright (c) 2022 Alejandro Colomar <alx.manpages@gmail.com>
+.\"
+.\" All rights reserved.
+.\"
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
+.\" Rewritten for the Linux man-pages by Alejandro Colomar
+.\"
+.TH sysexits.h 3head 2022-07-29 GNU "Linux Programmer's Manual"
+.SH NAME
+sysexits.h \- exit codes for programs
+.SH SYNOPSIS
+.nf
+.B #include <sysexits.h>
+.fi
+.TS
+lB2 lB2 l1 lX.
+#define EX_OK	0	/*	T{
+successful termination */
+T}
+.PP
+#define EX__BASE	64	/*	T{
+base value for error messages */
+T}
+.PP
+#define EX_USAGE	64	/*	T{
+command line usage error */
+T}
+#define EX_DATAERR	65	/*	T{
+data format error */
+T}
+#define EX_NOINPUT	66	/*	T{
+cannot open input */
+T}
+#define EX_NOUSER	67	/*	T{
+addressee unknown */
+T}
+#define EX_NOHOST	68	/*	T{
+host name unknown */
+T}
+#define EX_UNAVAILABLE	69	/*	T{
+service unavailable */
+T}
+#define EX_SOFTWARE	70	/*	T{
+internal software error */
+T}
+#define EX_OSERR	71	/*	T{
+system error (e.g., can't fork) */
+T}
+#define EX_OSFILE	72	/*	T{
+critical OS file missing */
+T}
+#define EX_CANTCREAT	73	/*	T{
+can't create (user) output file */
+T}
+#define EX_IOERR	74	/*	T{
+input/output error */
+T}
+#define EX_TEMPFAIL	75	/*	T{
+temp failure; user is invited to retry */
+T}
+#define EX_PROTOCOL	76	/*	T{
+remote error in protocol */
+T}
+#define EX_NOPERM	77	/*	T{
+permission denied */
+T}
+#define EX_CONFIG	78	/*	T{
+configuration error */
+T}
+.PP
+.T&
+lB2 l2 l1 lX.
+#define EX__MAX	...	/*	T{
+maximum listed value */
+T}
+.TE
+.SH DESCRIPTION
+A few programs exit with the following error codes.
+.PP
+The successful exit is always indicated by a status of
+.BR 0 ,
+or
+.B EX_OK
+(equivalent to
+.B EXIT_SUCCESS
+from
+.IR <stdlib.h> ).
+Error numbers begin at
+.B EX__BASE
+to reduce the possibility of clashing with other exit statuses
+that random programs may already return.
+The meaning of the code is approximately as follows:
+.TP
+.B EX_USAGE
+The command was used incorrectly,
+e.g.,
+with the wrong number of arguments,
+a bad flag,
+bad syntax in a parameter,
+or whatever.
+.TP
+.B EX_DATAERR
+The input data was incorrect in some way.
+This should only be used for user's data and not system files.
+.TP
+.B EX_NOINPUT
+An input file (not a system file) did not exist or was not readable.
+This could also include errors like "No message" to a mailer
+(if it cared to catch it).
+.TP
+.B EX_NOUSER
+The user specified did not exist.
+This might be used for mail addresses or remote logins.
+.TP
+.B EX_NOHOST
+The host specified did not exist.
+This is used in mail addresses or network requests.
+.TP
+.B EX_UNAVAILABLE
+A service is unavailable.
+This can occur if a support program or file does not exist.
+This can also be used as a catch-all message
+when something you wanted to do doesn't work, but you don't know why.
+.TP
+.B EX_SOFTWARE
+An internal software error has been detected.
+This should be limited to non-operating system related errors if possible.
+.TP
+.B EX_OSERR
+An operating system error has been detected.
+This is intended to be used for such things as
+"cannot fork",
+"cannot create pipe",
+or the like.
+It includes things like
+.BR getuid (2)
+returning a user that does not exist in the
+.BR passwd (5)
+file.
+.TP
+.B EX_OSFILE
+Some system file
+(e.g.,
+.IR /etc/passwd ,
+.IR /etc/utmp ,
+etc.)
+does not exist,
+cannot be opened,
+or has some sort of error (e.g., syntax error).
+.TP
+.B EX_CANTCREAT
+A (user specified) output file cannot be created.
+.TP
+.B EX_IOERR
+An error occurred while doing I/O on some file.
+.TP
+.B EX_TEMPFAIL
+Temporary failure,
+indicating something that is not really an error.
+For example that a mailer could not create a connection,
+and the request should be reattempted later.
+.TP
+.B EX_PROTOCOL
+The remote system returned something that
+was "not possible" during a protocol exchange.
+.TP
+.B EX_OSFILE
+You did not have sufficient permission to perform the operation.
+This is not intended for file system problems,
+which should use
+.B EX_NOINPUT
+or
+.BR EX_CANTCREAT ,
+but rather for higher level permissions.
+.TP
+.B EX_CONFIG
+Something was found in an unconfigured or misconfigured state.
+.PP
+The numerical values corresponding to the symbolical ones
+are given in parenthesis for easy reference.
+.SH STANDARDS
+Not in POSIX.1.
+Present on the BSDs.
+The
+.I <sysexits.h>
+file appeared in 4.0BSD for use by the deliverymail utility,
+later renamed to
+.BR sendmail (8).
+.SH BUGS
+The choice of an appropriate exit value is often ambiguous.
+.SH SEE ALSO
+.BR err (3),
+.BR error (3),
+.BR exit (3)