.\"
.\"	aegis - project change supervisor
.\"	Copyright (C) 1998 Peter Miller;
.\"	All rights reserved.
.\"
.\"	This program is free software; you can redistribute it and/or modify
.\"	it under the terms of the GNU General Public License as published by
.\"	the Free Software Foundation; either version 2 of the License, or
.\"	(at your option) any later version.
.\"
.\"	This program is distributed in the hope that it will be useful,
.\"	but WITHOUT ANY WARRANTY; without even the implied warranty of
.\"	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\"	GNU General Public License for more details.
.\"
.\"	You should have received a copy of the GNU General Public License
.\"	along with this program; if not, write to the Free Software
.\"	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
.\"
.\" MANIFEST: AUUGN Feb'98 Article
.\"
.nr PS 72
.nr VS 75000
.LP
.ad c
What Make Does
.br
.ad l
.sp 0.3i
.nr PS 36
.nr VS 37
.XP
\(bu
It works out the order to do things,
from the information you give it.
.br
.ps 20
.vs 21
.nf
.ft CW
.sp 0.5
prog: a.o b.o
    cc a.o b.o -o prog
.sp 0.5
a.o: a.c a.h
    cc -c a.c
.sp 0.5
b.o: b.c a.h
    cc -c b.c
.sp 0.5
a.c a.h: a.y
    yacc -d a.y
    mv y.tab.c a.c
    mv y.tab.h a.h
.ft P
.fi
.XP
\(bu
It's not a fancy shell interpreter.
.bp
.nr PS 24
.nr VS 25
.XP
\(bu
Make works out the order to do things,
from the information you give it.
This is in the form of ``this file before that file'' sets.
.XP
\(bu
Make is not a fancy shell interpreter.
.br
\(dg It doesn't do things in the order you say.
.br
\(dg You can continue after errors
.br
\(dg You can parallelize things
.br
\(dg Plus nine billion other options
.XP
\(bu
Make is goal driven \- you tell it what you want,
and it tries to find a way to do it.
.XP
\(bu
Even if you have a sources macro, which you text bash to get the objects,
\fImake\fP will apply all its rules to try to find a way to build the
\fIobjects\fP.
.bp
.XP
\(bu
It's not a fancy shell interpreter.
.br
.ps 16
.vs 17
.nf
.ft CW
.sp 0.5
#!/bin/sh
# \fIin particular, it doesn't say this\fP
if test ! -e a.c -o a.y -nt a.c \e
    -o ! -e a.h -o a.y -nt a.h
then
    echo "yacc -d a.y"
    ( yacc -d a.y ) || exit 1
    echo "mv y.tab.c a.c"
    ( mv y.tab.c a.c ) || exit 1
    echo "mv y.tab.h a.h"
    ( mv y.tab.h a.h ) || exit 1
fi
if test ! -e a.o \e
    -o a.c -nt a.o \e
    -o a.h -nt a.o
then
    echo "cc -c a.c"
    ( cc -c a.c ) || exit 1
fi
if test ! -e b.o \e
    -o b.c -nt b.o \e
    -o a.h -nt b.o
then
    echo "cc -c b.c"
    ( cc -c b.c ) || exit 1
fi
if test ! -e prog \e
    -o a.o -nt prog \e
    -o b.o -nt prog
then
    echo "cc -o prog a.o b.o"
    ( cc -o prog a.o b.o ) || exit 1
fi
exit 0
.ft R
.fi
.bp
.XP
\(bu
It's not a fancy shell interpreter.
.br
\(dg \fIIt doesn't do things in the order you say.\fP
.br
\(dg You can continue after errors
.br
\(dg You can parallelize things
.br
\(dg Plus nine billion other options