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INSTALLATION INSTRUCTIONS for the Independent JPEG Group's JPEG software

Copyright (C) 1991-1998, Thomas G. Lane.

This file is part of the Independent JPEG Group's software.

For conditions of distribution and use, see the accompanying README file.

This file explains how to configure and install the IJG software. We have

tried to make this software extremely portable and flexible, so that it can be

adapted to almost any environment. The downside of this decision is that the

installation process is complicated. We have provided shortcuts to simplify

If you are on a Unix machine, you may not need to read this file at all.

Try doing

./configure

make

make test

If that doesn't complain, do

make install

(better do "make -n install" first to see if the makefile will put the files

where you want them). Read further if you run into snags or want to customize

the code for your system.

by hand

Building the software

Testing the software

Installing the software

Optional stuff

Optimization

Hints for specific systems

BEFORE YOU START

================

Before installing the software you must unpack the distributed source code.

self-test will give bad results.

Please check the last section of this file to see if there are hints for the

specific machine or compiler you are using.

CONFIGURING THE SOFTWARE

========================

To configure the IJG code for your system, you need to create two files:

* jconfig.h: contains values for system-dependent #define symbols.

* Makefile: controls the compilation process.

(On a non-Unix machine, you may create "project files" or some other

substitute for a Makefile. jconfig.h is needed in any environment.)

We provide three different ways to generate these files:

* On a Unix system, you can just run the "configure" script.

* We provide sample jconfig files and makefiles for popular machines;

* If all else fails, read the instructions below and make your own files.

If you are on a Unix machine, you can just type

./configure

and let the configure script construct appropriate configuration files.

If you're using "csh" on an old version of System V, you might need to type

sh configure

instead to prevent csh from trying to execute configure itself.

Expect configure to run for a few minutes, particularly on slower machines;

it works by compiling a series of test programs.

Configure was created with GNU Autoconf and it follows the usual conventions

for GNU configure scripts. It makes a few assumptions that you may want to

override. You can do this by providing optional switches to configure:

./configure --enable-shared

running configure without either switch; that should build a static library

without using libtool. If that works, your problem is probably with libtool

not with the IJG code. libtool is fairly new and doesn't support all flavors

of Unix yet. (You might be able to find a newer version of libtool than the

one included with libjpeg; see ftp.gnu.org. Report libtool problems to

bug-libtool@gnu.org.)

./configure CC='cc'

The same method can be used to include any unusual compiler switches.

./configure CC='cc -Aa'

into /usr/local/bin, /usr/local/man, etc. You can specify an installation

prefix other than "/usr/local" by giving configure the option "--prefix=PATH".

software's internal virtual memory mechanism. To do this, give the option

"--enable-maxmem=N" where N is the default maxmemory limit in megabytes.

You probably don't need to worry about this on reasonably-sized Unix machines,

unless you plan to process very large images.

Configure has some other features that are useful if you are cross-compiling

or working in a network of multiple machine types; but if you need those

features, you probably already know how to use them.

Configuring the software using one of the supplied jconfig and makefile files

If you have one of these systems, you can just use the provided configuration

makefile.manx jconfig.manx Amiga, Manx Aztec C

makefile.sas jconfig.sas Amiga, SAS C

makeproj.mac jconfig.mac Apple Macintosh, Metrowerks CodeWarrior

mak*jpeg.st jconfig.st Atari ST/STE/TT, Pure C or Turbo C

makefile.bcc jconfig.bcc MS-DOS or OS/2, Borland C

makefile.dj jconfig.dj MS-DOS, DJGPP (Delorie's port of GNU C)

makefile.mc6 jconfig.mc6 MS-DOS, Microsoft C (16-bit only)

makefile.wat jconfig.wat MS-DOS, OS/2, or Windows NT, Watcom C

makefile.vc jconfig.vc Windows NT/95, MS Visual C++

make*.ds jconfig.vc Windows NT/95, MS Developer Studio

makefile.mms jconfig.vms Digital VMS, with MMS software

makefile.vms jconfig.vms Digital VMS, without MMS software

the appropriate system-specific hints section near the end of this file.

First, generate a jconfig.h file. If you are moderately familiar with C,

the comments in jconfig.doc should be enough information to do this; just

copy jconfig.doc to jconfig.h and edit it appropriately. Otherwise, you may

prefer to use the ckconfig.c program. You will need to compile and execute

ckconfig.c by hand --- we hope you know at least enough to do that.

ckconfig.c may not compile the first try (in fact, the whole idea is for it

you get it to run, it will write a suitable jconfig.h file, and will also

print out some advice about which makefile to use.

You may also want to look at the canned jconfig files, if there is one for a

makefile.unix: if not.

in jconfig.h.) You may want to start from one of the other makefiles if

there is one for a system similar to yours.

you may want to change the CC and CFLAGS definitions. For instance, if you

are using GCC, set CC=gcc. If you had to use any compiler switches to get

If you are on a system that doesn't use makefiles, you'll need to set up

project files (or whatever you do use) to compile all the source files and

link them into executable files cjpeg, djpeg, jpegtran, rdjpgcom, and wrjpgcom.

See the file lists in any of the makefiles to find out which files go into

each program. Note that the provided makefiles all make a "library" file

libjpeg first, but you don't have to do that if you don't want to; the file

lists identify which source files are actually needed for compression,

decompression, or both. As a last resort, you can make a batch script that

------------------

These programs can use a Unix-like command line style which supports

redirection and piping, like this:

cjpeg inputfile >outputfile

cjpeg <inputfile >outputfile

source program | cjpeg >outputfile

The simpler "two file" command line style is just

cjpeg inputfile outputfile

You may prefer the two-file style, particularly if you don't have pipes.

You MUST use two-file style on any system that doesn't cope well with binary

data fed through stdin/stdout; this is true for some MS-DOS compilers, for

fdopen() library routine or a Microsoft-compatible setmode() routine, you

Selecting a memory manager

--------------------------

The IJG code is capable of working on images that are too big to fit in main

memory; data is swapped out to temporary files as necessary. However, the

code to do this is rather system-dependent. We provide five different

* jmemansi.c This version uses the ANSI-standard library routine tmpfile(),

which not all non-ANSI systems have. On some systems

location; if you don't like what it does, use jmemname.c.

are removed if the program is aborted.

* jmemnobs.c (That stands for No Backing Store :-).) This will compile on

almost any system, but it assumes you have enough main memory

or virtual memory to hold the biggest images you work with.

* jmemdos.c This should be used with most 16-bit MS-DOS compilers.

See the system-specific notes about MS-DOS for more info.

jconfig.h, and include the assembly file jmemdosa.asm in the

programs. The supplied makefiles and jconfig files for

16-bit MS-DOS compilers already do both.

* jmemmac.c Custom version for Apple Macintosh; see the system-specific

notes for Macintosh for more info.

To use a particular memory manager, change the SYSDEPMEM variable in your

makefile to equal the corresponding object file name (for example, jmemansi.o

If you have plenty of (real or virtual) main memory, just use jmemnobs.c.

You may also need to change unlink() to remove() in close_backing_store().

Except with jmemnobs.c or jmemmac.c, you need to adjust the DEFAULT_MAX_MEM

setting to a reasonable value for your system (either by adding a #define for

DEFAULT_MAX_MEM to jconfig.h, or by adding a -D switch to the Makefile).

This value limits the amount of data space the program will attempt to

allocate. Code and static data space isn't counted, so the actual memory

needs for cjpeg or djpeg are typically 100 to 150Kb more than the max-memory

setting. Larger max-memory settings reduce the amount of I/O needed to

process a large image, but too large a value can result in "insufficient

memory" failures. On most Unix machines (and other systems with virtual

memory), just set DEFAULT_MAX_MEM to several million and forget it. At the

other end of the spectrum, for MS-DOS machines you probably can't go much

Now you should be able to compile the software. Just say "make" (or

whatever's necessary to start the compilation). Have a cup of coffee.

Here are some things that could go wrong:

If your compiler complains about undefined structures, you should be able to

shut it up by putting "#define INCOMPLETE_TYPES_BROKEN" in jconfig.h.

wrong ones, read jinclude.h. This shouldn't happen if you used configure

or ckconfig.c to set up jconfig.h.

There are a fair number of routines that do not use all of their parameters;

Also see the system-specific hints, below.

TESTING THE SOFTWARE

====================

As a quick test of functionality we've included a small sample image in