ExtUtils::MakeMaker - create an extension Makefile


use ExtUtils::MakeMaker;

WriteMakefile( ATTRIBUTE => VALUE [, ...] );

which is really



This utility is designed to write a Makefile for an extension module from a Makefile.PL. It is based on the Makefile.SH model provided by Andy Dougherty and the perl5-porters.

It splits the task of generating the Makefile into several subroutines that can be individually overridden. Each subroutine returns the text it wishes to have written to the Makefile.

Hintsfile support uses the architecture specific information from In addition it evaluates architecture specific hints files in a hints/ directory. The hints files are expected to be named like their counterparts in PERL_SRC/hints, but with an .pl file name extension (eg. They are simply evaled by MakeMaker within the WriteMakefile() subroutine, and can be used to execute commands as well as to include special variables. The rules which hintsfile is chosen are the same as in Configure.

The hintsfile is eval()ed immediately after the arguments given to WriteMakefile are stuffed into a hash reference $self but before this reference becomes blessed. So if you want to do the equivalent to override or create an attribute you would say something like

    $self->{LIBS} = ['-ldbm -lucb -lc'];

What's new in version 5 of MakeMaker

MakeMaker 5 is pure object oriented. This allows us to write an unlimited number of Makefiles with a single perl process. 'perl Makefile.PL' with MakeMaker 5 goes through all subdirectories immediately and evaluates any Makefile.PL found in the next level subdirectories. The benefit of this approach comes in useful for both single and multi directories extensions.

Multi directory extensions have an immediately visible speed advantage, because there's no startup penalty for any single subdirectory Makefile.

Single directory packages benefit from the much improved needs_linking() method. As the main Makefile knows everything about the subdirectories, a needs_linking() method can now query all subdirectories if there is any linking involved down in the tree. The speedup for PM-only Makefiles seems to be around 1 second on my Indy 100 MHz.

Incompatibilities between MakeMaker 5.00 and 4.23

There are no incompatibilities in the short term, as all changes are accompanied by short-term workarounds that guarantee full backwards compatibility.

You are likely to face a few warnings that expose deprecations which will result in incompatibilities in the long run:

You should not use %att directly anymore. Instead any subroutine you override in the MY package will be called by the object method, so you can access all object attributes directly via the object in $_[0].

You should not call the class methos MM->something anymore. Instead you should call the superclass. Something like

    sub MY::constants {
        my $self = shift;

Especially the libscan() and exescan() methods should be altered towards OO programming, that means do not expect that $_ to contain the path but rather $_[1].

You should program with more care. Watch out for any MakeMaker variables. Do not try to alter them, somebody else might depend on them. E.g. do not overwrite the ExtUtils::MakeMaker::VERSION variable (this happens if you import it and then set it to the version number of your package), do not expect that the INST_LIB variable will be ./blib (do not 'unshift @INC, "./blib" and do not use "blib/"). Do not croak in your Makefile.PL, let it fail with a warning instead.

Try to build several extensions simultanously to debug your Makefile.PL. You can unpack a bunch of distributed packages, so your directory looks like

    Alias-1.00/         Net-FTP-1.01a/      Set-Scalar-0.001/
    ExtUtils-Peek-0.4/  Net-Ping-1.00/      SetDualVar-1.0/
    Filter-1.06/        NetTools-1.01a/     Storable-0.1/
    GD-1.00/            Religion-1.04/      Sys-Domain-1.05/
    MailTools-1.03/     SNMP-1.5b/          Term-ReadLine-0.7/

and write a dummy Makefile.PL that contains nothing but

    use ExtUtils::MakeMaker;

That's actually fun to watch :)

Final suggestion: Try to delete all of your MY:: subroutines and watch, if you really still need them. MakeMaker might already do what you want without them. That's all about it.

Default Makefile Behaviour

The automatically generated Makefile enables the user of the extension to invoke

  perl Makefile.PL # optionally "perl Makefile.PL verbose"
  make test        # optionally set TEST_VERBOSE=1
  make install     # See below

The Makefile to be produced may be altered by adding arguments of the form KEY=VALUE. If the user wants to work with a different perl than the default, this can be achieved with

  perl Makefile.PL PERL=/tmp/myperl5

Other interesting targets in the generated Makefile are

  make config     # to check if the Makefile is up-to-date
  make clean      # delete local temp files (Makefile gets renamed)
  make realclean  # delete derived files (including ./blib)
  make dist       # see below the Distribution Support section

Special case make install

make alone puts all relevant files into directories that are named by the macros INST_LIB, INST_ARCHLIB, INST_EXE, INST_MAN1DIR, and INST_MAN3DIR. All these default to ./blib or something below blib if you are not building below the perl source directory. If you are building below the perl source, INST_LIB and INST_ARCHLIB default to ../../lib, and INST_EXE is not defined.

The install target of the generated Makefile is a recursive call to make which sets


The INSTALL... macros in turn default to their %Config ($Config{installprivlib}, $Config{installarchlib}, etc.) counterparts.

The recommended way to proceed is to set only the INSTALL* macros, not the INST_* targets. In doing so, you give room to the compilation process without affecting important directories. Usually a make test will succeed after the make, and a make install can finish the game.

MakeMaker gives you much more freedom than needed to configure internal variables and get different results. It is worth to mention, that make(1) also lets you configure most of the variables that are used in the Makefile. But in the majority of situations this will not be necessary, and should only be done, if the author of a package recommends it.

The usual relationship between INSTALLPRIVLIB and INSTALLARCHLIB is that the latter is a subdirectory of the former with the name $Config{archname}, MakeMaker supports the user who sets INSTALLPRIVLIB. If INSTALLPRIVLIB is set, but INSTALLARCHLIB not, then MakeMaker defaults the latter to be INSTALLPRIVLIB/ARCHNAME if that directory exists, otherwise it defaults to INSTALLPRIVLIB.

PREFIX attribute

The PREFIX attribute can be used to set the INSTALL* attributes in one go. The quickest way to install a module in a non-standard place

    perl Makefile.PL PREFIX=~

This will replace the string specified by $Config{prefix} in all $Config{install*} values.

Note, that the tilde expansion is done by MakeMaker, not by perl by default, nor by make.

It is important to know, that the INSTALL* macros should be absolute paths, never relativ ones. Packages with multiple Makefile.PLs in different directories get the contents of the INSTALL* macros propagated verbatim. (The INST_* macros will be corrected, if they are relativ paths, but not the INSTALL* macros.)

If the user has superuser privileges, and is not working on AFS (Andrew File System) or relatives, then the defaults for INSTALLPRIVLIB, INSTALLARCHLIB, INSTALLBIN, etc. will be appropriate, and this incantation will be the best:

    perl Makefile.PL; make; make test
    make install

make install per default writes some documentation of what has been done into the file $(INSTALLARCHLIB)/perllocal.pod. This is an experimental feature. It can be bypassed by calling make pure_install.

AFS users

will have to specify the installation directories as these most probably have changed since perl itself has been installed. They will have to do this by calling

    perl Makefile.PL INSTALLPRIVLIB=/afs/here/today \
        INSTALLBIN=/afs/there/now INSTALLMAN3DIR=/afs/for/manpages

In nested extensions with many subdirectories, the INSTALL* arguments will get propagated to the subdirectories. Be careful to repeat this procedure every time you recompile an extension, unless you are sure the AFS istallation directories are still valid.

Static Linking of a new Perl Binary

An extension that is built with the above steps is ready to use on systems supporting dynamic loading. On systems that do not support dynamic loading, any newly created extension has to be linked together with the available resources. MakeMaker supports the linking process by creating appropriate targets in the Makefile whenever an extension is built. You can invoke the corresponding section of the makefile with

    make perl

That produces a new perl binary in the current directory with all extensions linked in that can be found in INST_ARCHLIB (which usually is ./blib) and PERL_ARCHLIB. To do that, MakeMaker writes a new Makefile, on UNIX, this is called Makefile.aperl (may be system dependent). If you want to force the creation of a new perl, it is recommended, that you delete this Makefile.aperl, so INST_ARCHLIB and PERL_ARCHLIB are searched-through for linkable libraries again.

The binary can be installed into the directory where perl normally resides on your machine with

    make inst_perl

To produce a perl binary with a different name than perl, either say

    perl Makefile.PL MAP_TARGET=myperl
    make myperl
    make inst_perl

or say

    perl Makefile.PL
    make myperl MAP_TARGET=myperl
    make inst_perl MAP_TARGET=myperl

In any case you will be prompted with the correct invocation of the inst_perl target that installs the new binary into INSTALLBIN.

Note, that there is a makeaperl scipt in the perl distribution, that supports the linking of a new perl binary in a similar fashion, but with more options.

make inst_perl per default writes some documentation of what has been done into the file $(INSTALLARCHLIB)/perllocal.pod. This can be bypassed by calling make pure_inst_perl.

Warning: the inst_perl: target is rather mighty and will probably overwrite your existing perl binary. Use with care!

Sometimes you might want to build a statically linked perl although your system supports dynamic loading. In this case you may explicitly set the linktype with the invocation of the Makefile.PL or make:

    perl Makefile.PL LINKTYPE=static    # recommended


    make LINKTYPE=static                # works on most systems

Determination of Perl Library and Installation Locations

MakeMaker needs to know, or to guess, where certain things are located. Especially INST_LIB and INST_ARCHLIB (where to install files into), PERL_LIB and PERL_ARCHLIB (where to read existing modules from), and PERL_INC (header files and libperl*.*).

Extensions may be built either using the contents of the perl source directory tree or from an installed copy of the perl library. The recommended way is to build extensions after you have run 'make install' on perl itself. Do that in a directory that is not below the perl source tree. The support for extensions below the ext directory of the perl distribution is only good for the standard extensions that come with perl.

If an extension is being built below the ext/ directory of the perl source then MakeMaker will set PERL_SRC automatically (e.g., ../..). If PERL_SRC is defined then other variables default to the following:

  PERL_LIB     = PERL_SRC/lib

If an extension is being built away from the perl source then MakeMaker will leave PERL_SRC undefined and default to using the installed copy of the perl library. The other variables default to the following:

  PERL_INC     = $archlib/CORE
  PERL_LIB     = $privlib
  PERL_ARCHLIB = $archlib
  INST_LIB     = ./blib
  INST_ARCHLIB = ./blib/<archname>

If perl has not yet been installed then PERL_SRC can be defined on the command line as shown in the previous section.

Useful Default Makefile Macros

FULLEXT = Pathname for extension directory (eg DBD/Oracle).

BASEEXT = Basename part of FULLEXT. May be just equal FULLEXT.

ROOTEXT = Directory part of FULLEXT with leading slash (eg /DBD)




Using Attributes (and Parameters)

The following attributes can be specified as arguments to WriteMakefile() or as NAME=VALUE pairs on the command line:


Ref to array of *.c file names. Initialised from a directory scan and the values portion of the XS attribute hash. This is not currently used by MakeMaker but may be handy in Makefile.PLs.


Arrayref. E.g. [qw(archname manext)] defines ARCHNAME & MANEXT from MakeMaker will add to CONFIG the following values anyway: ar cc cccdlflags ccdlflags dlext dlsrc ld lddlflags ldflags libc lib_ext obj_ext ranlib so


CODE reference. Extension writers are requested to do all their initializing within that subroutine. The subroutine should return a hash reference. The hash may contain further attributes, e.g. {LIBS => ...}, that have to be determined by some evaluation method.


Something like "-DHAVE_UNISTD_H"


Ref to array of subdirectories containing Makefile.PLs e.g. [ 'sdbm' ] in ext/SDBM_File


Your name for distributing the package (by tar file) This defaults to NAME above.


Hashref of symbol names for routines to be made available as universal symbols. Each key/value pair consists of the package name and an array of routine names in that package. Used only under AIX (export lists) and VMS (linker options) at present. The routine names supplied will be expanded in the same way as XSUB names are expanded by the XS() macro. Defaults to

  {"$(NAME)" => ["boot_$(NAME)" ] }


  {"RPC" => [qw( boot_rpcb rpcb_gettime getnetconfigent )],
   "NetconfigPtr" => [ 'DESTROY'] }

Array of symbol names for variables to be made available as universal symbols. Used only under AIX (export lists) and VMS (linker options) at present. Defaults to []. (e.g. [ qw( Foo_version Foo_numstreams Foo_tree ) ])


Ref to array of executable files. The files will be copied to the INST_EXE directory. Make realclean will delete them from there again.


The name of the Makefile to be produced. Defaults to the contents of MAKEFILE, but can be overridden. This is used for the second Makefile that will be produced for the MAP_TARGET.


Perl binary able to run this extension.


Ref to array of *.h file names. Similar to C.


Include file dirs eg: "-I/usr/5include -I/path/to/inc"


Used by 'make install', which sets INST_ARCHLIB to this value.


Used by 'make install' which sets INST_EXE to this value.


This directory gets the man pages at 'make install' time. Defaults to $Config{installman1dir}.


This directory gets the man pages at 'make install' time. Defaults to $Config{installman3dir}.


Used by 'make install', which sets INST_LIB to this value.


Same as INST_LIB for architecture dependent files.


Directory, where executable scripts should be installed during 'make'. Defaults to "./blib/ARCHNAME", just to have a dummy location during testing. make install will set INST_EXE to INSTALLBIN.


Directory where we put library files of this extension while building it.


Directory to hold the man pages at 'make' time


Directory to hold the man pages at 'make' time


defaults to "$(OBJECT)" and is used in the ld command to specify what files to link/load from (also see dynamic_lib below for how to specify ld flags)


The filename of the perllibrary that will be used together with this extension. Defaults to libperl.a.


An anonymous array of alternative library specifications to be searched for (in order) until at least one library is found. E.g.

  'LIBS' => ["-lgdbm", "-ldbm -lfoo", "-L/path -ldbm.nfs"]

Mind, that any element of the array contains a complete set of arguments for the ld command. So do not specify

  'LIBS' => ["-ltcl", "-ltk", "-lX11"]

See ODBM_File/Makefile.PL for an example, where an array is needed. If you specify a scalar as in

  'LIBS' => "-ltcl -ltk -lX11"

MakeMaker will turn it into an array with one element.


'static' or 'dynamic' (default unless usedl=undef in Should only be used to force static linking (also see linkext below).


Boolean which tells MakeMaker, that it should include the rules to make a perl. This is handled automatically as a switch by MakeMaker. The user normally does not need it.


The name of the Makefile to be produced.


Hashref of pod-containing files. MakeMaker will default this to all EXE_FILES files that include POD directives. The files listed here will be converted to man pages and installed as was requested at Configure time.


Hashref of .pm and .pod files. MakeMaker will default this to all .pod and any .pm files that include POD directives. The files listed here will be converted to man pages and installed as was requested at Configure time.


If it is intended, that a new perl binary be produced, this variable may hold a name for that binary. Defaults to perl


If the extension links to a library that it builds set this to the name of the library (see SDBM_File)


Perl module name for this extension (DBD::Oracle). This will default to the directory name but should be explicitly defined in the Makefile.PL.


MakeMaker will figure out, if an extension contains linkable code anywhere down the directory tree, and will set this variable accordingly, but you can speed it up a very little bit, if you define this boolean variable yourself.


Boolean. Experimental attribute to inhibit descending into subdirectories.


List of object files, defaults to '$(BASEEXT)$(OBJ_EXT)', but can be a long string containing all object files, e.g. "tkpBind.o tkpButton.o tkpCanvas.o"


Perl binary for tasks that can be done by miniperl


The call to the program that is able to compile perlmain.c. Defaults to $(CC).


Same as above for architecture dependent files


Directory containing the Perl library to use.


Directory containing the Perl source code (use of this should be avoided, it may be undefined)


Ref to hash of files to be processed as perl programs. MakeMaker will default to any found *.PL file (except Makefile.PL) being keys and the basename of the file being the value. E.g.

  {'foobar.PL' => 'foobar'}

The *.PL files are expected to produce output to the target files themselves.


Hashref of .pm files and *.pl files to be installed. e.g.

  {'' => '$(INST_LIBDIR)/'}

By default this will include *.pm and *.pl. If a lib directory exists and is not listed in DIR (above) then any *.pm and *.pl files it contains will also be included by default. Defining PM in the Makefile.PL will override PMLIBDIRS.


Ref to array of subdirectories containing library files. Defaults to [ 'lib', $(BASEEXT) ]. The directories will be scanned and any files they contain will be installed in the corresponding location in the library. A libscan() method can be used to alter the behaviour. Defining PM in the Makefile.PL will override PMLIBDIRS.


Can be used to set the three INSTALL* attributes in one go (except for INSTALLMAN1DIR). They will have PREFIX as a common directory node and will branch from that node into lib/, lib/ARCHNAME, and bin/ unless you override one of them.


Placeholder, not yet implemented. Will eventually be a hashref: Names of modules that need to be available to run this extension (e.g. Fcntl for SDBM_File) are the keys of the hash and the desired version is the value. Needs further evaluation, should probably allow to define prerequisites among header files, libraries, perl version, etc.


Arryref. E.g. [qw(name1 name2)] skip (do not write) sections of the Makefile


Ref to array of typemap file names. Use this when the typemaps are in some directory other than the current directory or when they are not named typemap. The last typemap in the list takes precedence. A typemap in the current directory has highest precedence, even if it isn't listed in TYPEMAPS. The default system typemap has lowest precedence.


Your version number for distributing the package. This defaults to 0.1.


Instead of specifying the VERSION in the Makefile.PL you can let MakeMaker parse a file to determine the version number. The parsing routine requires that the file named by VERSION_FROM contains one single line to compute the version number. The first line in the file that contains the regular expression


will be evaluated with eval() and the value of the named variable after the eval() will be assigned to the VERSION attribute of the MakeMaker object. The following lines will be parsed o.k.:

    $VERSION = '1.00';
    ( $VERSION ) = '$Revision: 1.135 $ ' =~ /\$Revision:\s+([^\s]+)/;
    $FOO::VERSION = '1.10';

but these will fail:

    my $VERSION = '1.01';
    local $VERSION = '1.02';
    local $FOO::VERSION = '1.30';

The file named in VERSION_FROM is added as a dependency to Makefile to guarantee, that the Makefile contains the correct VERSION macro after a change of the file.


Hashref of .xs files. MakeMaker will default this. e.g.

  {'name_of_file.xs' => 'name_of_file.c'}

The .c files will automatically be included in the list of files deleted by a make clean.


String of options to pass to xsubpp. This might include -C++ or -extern. Do not include typemaps here; the TYPEMAP parameter exists for that purpose.


May be set to an empty string, which is identical to -prototypes, or -noprototypes. See the xsubpp documentation for details. MakeMaker defaults to the empty string.


Your version number for the .xs file of this package. This defaults to the value of the VERSION attribute.

Additional lowercase attributes

can be used to pass parameters to the methods which implement that part of the Makefile. These are not normally required:

  {FILES => "*.xyz foo"}
  {TARFLAGS => 'cvfF', COMPRESS => 'gzip', SUFFIX => 'gz',
  SHAR => 'shar -m', DIST_CP => 'ln'}

If you specify COMPRESS, then SUFFIX should also be altered, as it is needed to tell make the target file of the compression. Setting DIST_CP to ln can be useful, if you need to preserve the timestamps on your files. DIST_CP can take the values 'cp', which copies the file, 'ln', which links the file, and 'best' which copies symbolic links and links the rest. Default is 'best'.

  {ARMAYBE => 'ar', OTHERLDFLAGS => '...', INST_DYNAMIC_DEP => '...'}
  {SPLITLIB => '$(INST_LIB)' (default) or '$(INST_ARCHLIB)'}
  {LINKTYPE => 'static', 'dynamic' or ''}

NB: Extensions that have nothing but *.pm files had to say

  {LINKTYPE => ''}

with Pre-5.0 MakeMakers. Since version 5.00 of MakeMaker such a line can be deleted safely. MakeMaker recognizes, when there's nothing to be linked.

  {FILES => '$(INST_ARCHAUTODIR)/*.xyz'}
  {MAXLEN =E<gt> 8}

Overriding MakeMaker Methods

If you cannot achieve the desired Makefile behaviour by specifying attributes you may define private subroutines in the Makefile.PL. Each subroutines returns the text it wishes to have written to the Makefile. To override a section of the Makefile you can either say:

        sub MY::c_o { "new literal text" }

or you can edit the default by saying something like:

        sub MY::c_o {
            my $self = shift;
            local *c_o;
            s/old text/new text/;

Both methods above are available for backwards compatibility with older Makefile.PLs.

If you still need a different solution, try to develop another subroutine, that fits your needs and submit the diffs to or comp.lang.perl.misc as appropriate.

Distribution Support

For authors of extensions MakeMaker provides several Makefile targets. Most of the support comes from the ExtUtils::Manifest module, where additional documentation can be found.

make distcheck

reports which files are below the build directory but not in the MANIFEST file and vice versa. (See ExtUtils::Manifest::fullcheck() for details)

make skipcheck

reports which files are skipped due to the entries in the MANIFEST.SKIP file (See ExtUtils::Manifest::skipcheck() for details)

make distclean

does a realclean first and then the distcheck. Note that this is not needed to build a new distribution as long as you are sure, that the MANIFEST file is ok.

make manifest

rewrites the MANIFEST file, adding all remaining files found (See ExtUtils::Manifest::mkmanifest() for details)

make distdir

Copies all the files that are in the MANIFEST file to a newly created directory with the name $(DISTNAME)-$(VERSION). If that directory exists, it will be removed first.

make disttest

Makes a distdir first, and runs a perl Makefile.PL, a make, and a make test in that directory.

make tardist

First does a command $(PREOP) which defaults to a null command. Does a distdir next and runs tar on that directory into a tarfile. Then deletes the distdir. Finishes with a command $(POSTOP) which defaults to a null command.

make dist

Defaults to $(DIST_DEFAULT) which in turn defaults to tardist.

make uutardist

Runs a tardist first and uuencodes the tarfile.

make shdist

First does a command $(PREOP) which defaults to a null command. Does a distdir next and runs shar on that directory into a sharfile. Then deletes the distdir. Finishes with a command $(POSTOP) which defaults to a null command. Note: For shdist to work properly a shar program that can handle directories is mandatory.

make ci

Does a $(CI) and a $(RCS_LABEL) on all files in the MANIFEST file.

Customization of the dist targets can be done by specifying a hash reference to the dist attribute of the WriteMakefile call. The following parameters are recognized:

    CI           ('ci -u')
    COMPRESS     ('compress')
    POSTOP       ('@ :')
    PREOP        ('@ :')
    RCS_LABEL    ('rcs -q -Nv$(VERSION_SYM):')
    SHAR         ('shar')
    SUFFIX       ('Z')
    TAR          ('tar')
    TARFLAGS     ('cvf')

An example:

    WriteMakefile( 'dist' => { COMPRESS=>"gzip", SUFFIX=>"gz" })


Andy Dougherty <>, Andreas König <A.Koenig@franz.ww.TU-Berlin.DE>, Tim Bunce <>. VMS support by Charles Bailey <bailey@HMIVAX.HUMGEN.UPENN.EDU>. Contact the makemaker mailing list, if you have any questions.


For a more complete documentation see the file Changes in the MakeMaker distribution package.


See the file Todo in the MakeMaker distribution package.