INSTALLATION INSTRUCTIONS for the Independent JPEG Group's JPEG softwareCopyright (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 havetried to make this software extremely portable and flexible, so that it can beadapted to almost any environment.  The downside of this decision is that theinstallation process is complicated.  We have provided shortcuts to simplifythe task on common systems.  But in any case, you will need at least a littlefamiliarity with C programming and program build procedures for your system.If you are only using this software as part of a larger program, the largerprogram's installation procedure may take care of configuring the IJG code.For example, Ghostscript's installation script will configure the IJG code.You don't need to read this file if you just want to compile Ghostscript.If you are on a Unix machine, you may not need to read this file at all.Try doing	./configure	make	make testIf that doesn't complain, do	make install(better do "make -n install" first to see if the makefile will put the fileswhere you want them).  Read further if you run into snags or want to customizethe code for your system.TABLE OF CONTENTS-----------------Before you startConfiguring the software:	using the automatic "configure" script	using one of the supplied jconfig and makefile files	by handBuilding the softwareTesting the softwareInstalling the softwareOptional stuffOptimizationHints for specific systemsBEFORE YOU START================Before installing the software you must unpack the distributed source code.Since you are reading this file, you have probably already succeeded in thistask.  However, there is a potential for error if you needed to convert thefiles to the local standard text file format (for example, if you are onMS-DOS you may have converted LF end-of-line to CR/LF).  You must applysuch conversion to all the files EXCEPT those whose names begin with "test".The test files contain binary data; if you change them in any way then theself-test will give bad results.Please check the last section of this file to see if there are hints for thespecific 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 othersubstitute 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 your machine matches one of the samples, just copy the right sample    files to jconfig.h and Makefile.  * If all else fails, read the instructions below and make your own files.Configuring the software using the automatic "configure" script---------------------------------------------------------------If you are on a Unix machine, you can just type	./configureand 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 configureinstead 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 conventionsfor GNU configure scripts.  It makes a few assumptions that you may want tooverride.  You can do this by providing optional switches to configure:* If you want to build libjpeg as a shared library, say	./configure --enable-sharedTo get both shared and static libraries, say	./configure --enable-shared --enable-staticNote that these switches invoke GNU libtool to take care of system-dependentshared library building methods.  If things don't work this way, please tryrunning configure without either switch; that should build a static librarywithout using libtool.  If that works, your problem is probably with libtoolnot with the IJG code.  libtool is fairly new and doesn't support all flavorsof Unix yet.  (You might be able to find a newer version of libtool than theone included with libjpeg; see ftp.gnu.org.  Report libtool problems tobug-libtool@gnu.org.)* Configure will use gcc (GNU C compiler) if it's available, otherwise cc.To force a particular compiler to be selected, use the CC option, for example	./configure CC='cc'The same method can be used to include any unusual compiler switches.For example, on HP-UX you probably want to say	./configure CC='cc -Aa'to get HP's compiler to run in ANSI mode.* The default CFLAGS setting is "-O" for non-gcc compilers, "-O2" for gcc.You can override this by saying, for example,	./configure CFLAGS='-g'if you want to compile with debugging support.* Configure will set up the makefile so that "make install" will install filesinto /usr/local/bin, /usr/local/man, etc.  You can specify an installationprefix other than "/usr/local" by giving configure the option "--prefix=PATH".* If you don't have a lot of swap space, you may need to enable the IJGsoftware's internal virtual memory mechanism.  To do this, give the option"--enable-maxmem=N" where N is the default maxmemory limit in megabytes.This is discussed in more detail under "Selecting a memory manager", below.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-compilingor working in a network of multiple machine types; but if you need thosefeatures, 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 configurationfiles:Makefile	jconfig file	System and/or compilermakefile.manx	jconfig.manx	Amiga, Manx Aztec Cmakefile.sas	jconfig.sas	Amiga, SAS Cmakeproj.mac	jconfig.mac	Apple Macintosh, Metrowerks CodeWarriormak*jpeg.st	jconfig.st	Atari ST/STE/TT, Pure C or Turbo Cmakefile.bcc	jconfig.bcc	MS-DOS or OS/2, Borland Cmakefile.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 Cmakefile.vc	jconfig.vc	Windows NT/95, MS Visual C++make*.ds	jconfig.vc	Windows NT/95, MS Developer Studiomakefile.mms	jconfig.vms	Digital VMS, with MMS softwaremakefile.vms	jconfig.vms	Digital VMS, without MMS softwareCopy the proper jconfig file to jconfig.h and the makefile to Makefile (orwhatever your system uses as the standard makefile name).  For more info seethe appropriate system-specific hints section near the end of this file.Configuring the software by hand--------------------------------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; justcopy jconfig.doc to jconfig.h and edit it appropriately.  Otherwise, you mayprefer to use the ckconfig.c program.  You will need to compile and executeckconfig.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 itto fail if anything is going to).  If you get compile errors, fix them byediting ckconfig.c according to the directions given in ckconfig.c.  Onceyou get it to run, it will write a suitable jconfig.h file, and will alsoprint out some advice about which makefile to use.You may also want to look at the canned jconfig files, if there is one for asystem similar to yours.Second, select a makefile and copy it to Makefile (or whatever your systemuses as the standard makefile name).  The most generic makefiles we provideare	makefile.ansi:	if your C compiler supports function prototypes	makefile.unix:	if not.(You have function prototypes if ckconfig.c put "#define HAVE_PROTOTYPES"in jconfig.h.)  You may want to start from one of the other makefiles ifthere is one for a system similar to yours.Look over the selected Makefile and adjust options as needed.  In particularyou may want to change the CC and CFLAGS definitions.  For instance, if youare using GCC, set CC=gcc.  If you had to use any compiler switches to getckconfig.c to work, make sure the same switches are in CFLAGS.If you are on a system that doesn't use makefiles, you'll need to set upproject files (or whatever you do use) to compile all the source files andlink 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 intoeach program.  Note that the provided makefiles all make a "library" filelibjpeg first, but you don't have to do that if you don't want to; the filelists identify which source files are actually needed for compression,decompression, or both.  As a last resort, you can make a batch script thatjust compiles everything and links it all together; makefile.vms is an exampleof this (it's for VMS systems that have no make-like utility).Here are comments about some specific configuration decisions you'llneed to make:Command line style------------------These programs can use a Unix-like command line style which supportsredirection and piping, like this:	cjpeg inputfile >outputfile	cjpeg <inputfile >outputfile	source program | cjpeg >outputfileThe simpler "two file" command line style is just	cjpeg inputfile outputfileYou 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 binarydata fed through stdin/stdout; this is true for some MS-DOS compilers, forexample.  If you're not on a Unix system, it's safest to assume you needtwo-file style.  (But if your compiler provides either the Posix-standardfdopen() library routine or a Microsoft-compatible setmode() routine, youcan safely use the Unix command line style, by defining USE_FDOPEN orUSE_SETMODE respectively.)To use the two-file style, make jconfig.h say "#define TWO_FILE_COMMANDLINE".Selecting a memory manager--------------------------The IJG code is capable of working on images that are too big to fit in mainmemory; data is swapped out to temporary files as necessary.  However, thecode to do this is rather system-dependent.  We provide five differentmemory managers:* jmemansi.c	This version uses the ANSI-standard library routine tmpfile(),		which not all non-ANSI systems have.  On some systems		tmpfile() may put the temporary file in a non-optimal		location; if you don't like what it does, use jmemname.c.* jmemname.c	This version creates named temporary files.  For anything		except a Unix machine, you'll need to configure the		select_file_name() routine appropriately; see the comments		near the head of jmemname.c.  If you use this version, define		NEED_SIGNAL_CATCHER in jconfig.h to make sure the temp files		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.		IMPORTANT: if you use this, define USE_MSDOS_MEMMGR in		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