:
##########################################################################
# Shellscript:	errno - show messages to system errors
# Version    :	0.3 (beta)
# Author     :	Heiner Steven (heiner.steven@odn.de)
# Date       :	19.07.95
# Category   :	Programming
# SCCS-Id.   :	$Id: errno,v 1.1.1.1 1999/06/15 19:29:05 heiner Exp $
##########################################################################
# Changes
# 21.09.95 hs	New parameter -l: list all error codes (0.2)
# 04.05.96 hs	Do not remove errno database for faster response time (0.3)
##########################################################################

PN=`basename $0`			# program name
VER='0.3 (beta)'

: ${GREP:=grep}
: ${ErrnoInc=/usr/include/sys/errno.h}	# Errno include file
Errnos=/tmp/$PN.db			# "database" with errnos

Usage () {
    echo "$PN - print name and description of error codes, $VER (stv '95)
usage: $PN {number|name|regex} [...]
   or  $PN -l
    -l 		list all error codes
    number	system error number, i.e. 10
    name	system error name, i.e. EPERM
    regex	string to 'grep' for" >&2
    exit 1
}

Msg () {
    for i
    do echo "$PN: $i" >&2
    done
}

Fatal () { Msg "$@"; exit 1; }

# Check arguments before setting them
getopt hl "$@" > /dev/null 2>&1	|| Usage
set -- `getopt hl "$@"`
while [ $# -gt 0 ]
do
    case "$1" in
	-l)	set -- '.'; break;;	# List all errnos
	--)	shift; break;;
	-h)	Usage;;
	-*)	Usage;;
	*)	break;;			# First argument
    esac
    shift
done

[ $# -lt 1 ] && Usage
[ -r "$ErrnoInc" ] || Fatal "cannot read $ErrnoInc"

[ -f "$Errnos" ] || {
    umask 000				# Everybody may read and write
    # Create "database" of errno values in the following format:
    #	2	ENOENT	No such file or directory
    nawk '
	# Example:
	# #define ENOENT          2    /* No such file or directory */
	($1 == "#define") && ($2 ~ /^E[A-Z][A-Z]*$/) && (NF >= 4) {
	    # $2=name, $3=errno
	    Desc = ""
	    for ( i=4; i<=NF; i++ ) {
		if ( $i == "/*" || $i == "*/" ) continue;
		# Remove commentmarkers from description:
		#	"/*Not owner*/" -> "Not owner"
		if ( $i ~ /^\/\*/ ) {
		    sub (/\/\*[ 	]*/, "", $i)
		} else if ( $i ~ /\*\/$/ ) {
		    sub (/[ 	]*\*\/$/, "", $i)
		}
		if ( Desc == "" )
		    Desc = $i
		else
		    Desc = Desc " " $i
	    }
	    print $3 "	" $2 "	" Desc
	}
    ' $ErrnoInc > "$Errnos" || exit	# nawk will print error message
}

# Search "database" for given strings
for i
do
    case "$i" in
	E[A-Z]*) Col=2;;	# Symbolic name given
	*[!0-9]*)		# No number: just grep for pattern
		$GREP -i "$i" "$Errnos"
		continue;;
	*)	Col=1;;		# This seems to be a number
    esac
    ${AWK:=nawk} '$'$Col' == "'$i'"' "$Errnos"
done