.\"
.\"	aegis - project change supervisor
.\"	Copyright (C) 1998, 2005-2008 Peter Miller
.\"
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.\"	it under the terms of the GNU General Public License as published by
.\"	the Free Software Foundation; either version 3 of the License, or
.\"	(at your option) any later version.
.\"
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.\"	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, see
.\"	<http://www.gnu.org/licenses/>.
.\"
.nr PS 72
.nr VS 75000
.LP
.ad c
But!
.br
.ad l
.sp 0.3i
.nr PS 36
.nr VS 37
.XP
\(bu A single makefile is Too Big
.XP
\(bu A single makefile is Too Complex
.XP
\(bu A single makefile is Not Modular
.XP
\(bu
It is too hard to write the rules
.XP
\(bu
The tools can't do it
.XP
\(bu
You'll run out of memory
.\" ---------------------------------------------------------------------------
.bp
.nr PS 24
.nr VS 25
.XP
\(bu
A single makefile is Too Big
.br
\(dg if it was all in a single file, it would be
.br
\(dg use include, and segment (same as recursive)
.br
\(dg total file size/count is the same
.XP
\(bu
A single makefile is Too Complex
.br
\(dg interactions between makefile segs are greater, \fBbut\fP
\(dg they contain the same information as now.
\(dg \fBR\fPigor in chosing variable names helps.
.XP
\(bu
A single makefile is Not Modular
\(dg Just as modular as recursive: same contents, same location.
.XP
\(bu
It is too hard to write the rules
.br
\(dg Nothing stops the rules from coping with directories \f(CW$(*D)
$(*F)\fP, \fIetc\fP
.br
\(dg You need add directory to all the filenames
.br
\(dg current directory at top, rule bodies written so
.XP
\(bu
The tools can't do it
.br
Some unresonable, some \[lq]help\[rq], most work
.XP
\(bu
You'll run out of memory
.br
\(dg Long long ago, on a CPU far far away \fImaybe\fP but
not on modern machines
.\" ---------------------------------------------------------------------------
.bp
.nr PS 72
.nr VS 75000
.LP
.ad c
But I only want to build My Little Bit!
.br
.ad l
.sp
.nr PS 36
.nr VS 37
.XP
\(bu Builds will take Too Long
.XP
\(bu Project Builds
.XP
\(bu Development Builds
.\" ---------------------------------------------------------------------------
.bp
.nr PS 24
.nr VS 25
.XP
\(bu Builds will take Too Long
.br
\(dg As described, is a whole project build
.br
\(dg This paper does not discusss the \fIefficient makefiles\fP portion
of the paper.
\(dg The stat(2)s are not the slow part.
.XP
\(bu Project Builds
.br
\(dg whole proj build explores all implications
(good if you don't know all 42M LOC)
.XP
\(bu Development Builds
.br
\(dg every developer, every time, \fByes\fP is too slow
\(dg use explicit target
.br
\(dg Use VPATH, avoids corrupting master source