pkg-config(1)						      General Commands Manual						     pkg-config(1)

NAME

       pkg-config - Return metainformation about installed libraries

SYNOPSIS

       pkg-config  [--modversion] [--help] [--print-errors] [--silence-errors] [--cflags] [--libs] [--libs-only-L] [--libs-only-l] [--cflags-only-
       I]  [--variable=VARIABLENAME]   [--define-variable=VARIABLENAME=VARIABLEVALUE]	[--uninstalled]   [--exists]   [--atleast-version=VERSION]
       [--exact-version=VERSION] [--max-version=VERSION] [LIBRARIES...]

DESCRIPTION

       The  pkg-config	program is used to retrieve information about installed libraries in the system.  It is typically used to compile and link
       against one or more libraries.  Here is a typical usage scenario in a Makefile:

       program: program.c
	    cc program.c `pkg-config --cflags --libs gnomeui`

       pkg-config retrieves information about packages from special metadata files. These files are named after the package,  with  the  extension
       .pc.  By default, pkg-config looks in the directory prefix/lib/pkgconfig for these files; it will also look in the colon-separated (on Win-
       dows, semicolon-separated) list of directories specified by the PKG_CONFIG_PATH environment variable.

       The package name specified on the pkg-config command line is defined to be the name of the metadata file, minus the  .pc  extension.  If  a
       library	can  install multiple versions simultaneously, it must give each version its own name (for example, GTK 1.2 might have the package
       name "gtk+" while GTK 2.0 has "gtk+-2.0").

OPTIONS

       The following options are supported:

       --modversion
	      Requests that the version information of the libraries specified on the command line be displayed.  If pkg-config can find  all  the
	      libraries  on  the  command  line, each library's version string is printed to stdout, one version per line. In this case pkg-config
	      exits successfully. If one or more libraries is unknown, pkg-config exits with a nonzero code, and the contents of stdout are  unde-
	      fined.

       --help Displays a help message and terminates.

       --print-errors
	      If  one  or  more  of  the modules on the command line, or their dependencies, are not found, or if an error occurs in parsing a .pc
	      file, then this option will cause errors explaining the problem to be printed. With "predicate" options such as "--exists"  pkg-con-
	      fig runs silently by default, because it's usually used in scripts that want to control what's output. This option can be used alone
	      (to just print errors encountered locating modules on the command line) or with other options. The PKG_CONFIG_DEBUG_SPEW environment
	      variable overrides this option.

       --silence-errors
	      If  one  or  more of the modules on the command line, or their dependencies, are not found, or if an error occurs in parsing a a .pc
	      file, then this option will keep errors explaining the problem from being printed. With "predicate" options such as "--exists"  pkg-
	      config  runs  silently  by  default, because it's usually used in scripts that want to control what's output. So this option is only
	      useful with options such as "--cflags" or "--modversion" that print errors by default. The PKG_CONFIG_DEBUG_SPEW	environment  vari-
	      able overrides this option.

       --errors-to-stdout
	      If printing errors, print them to stdout rather than the default stderr

       The following options are used to compile and link programs:

       --cflags
	      This  prints  pre-processor  and	compile  flags required to compile the packages on the command line, including flags for all their
	      dependencies. Flags are "compressed" so that each identical flag appears only once. pkg-config exits with a nonzero code if it can't
	      find metadata for one or more of the packages on the command line.

       --libs This  option  is identical to "--cflags", only it prints the link flags. As with "--cflags", duplicate flags are merged (maintaining
	      proper ordering), and flags for dependencies are included in the output.

       --libs-only-L
	      This prints the -L/-R part of "--libs". That is, it defines the library search path but doesn't  specify	which  libraries  to  link
	      with.

       --libs-only-l
	      This  prints  the  -l  part  of "--libs" for the libraries specified on the command line. Note that the union of "--libs-only-l" and
	      "--libs-only-L" may be smaller than "--libs", due to flags such as -rdynamic.

       --variable=VARIABLENAME
	      This returns the value of a variable defined in a package's .pc file. Most packages define the variable "prefix",  for  example,	so
	      you can say:
		$ pkg-config --variable=prefix glib-2.0
		/usr/

       --define-variable=VARIABLENAME=VARIABLEVALUE
	      This  sets  a  global  value  for a variable, overriding the value in any .pc files. Most packages define the variable "prefix", for
	      example, so you can say:
		$ pkg-config --print-errors --define-variable=prefix=/foo 
			     --variable=prefix glib-2.0
		/foo

       --uninstalled
	      Normally if you request the package "foo" and the package "foo-uninstalled" exists, pkg-config will prefer the "-uninstalled"  vari-
	      ant. This allows compilation/linking against uninstalled packages. If you specify the "--uninstalled" option, pkg-config will return
	      successfully if any "-uninstalled" packages are being used, and return failure (false)  otherwise.   (The  "PKG_CONFIG_DISABLE_UNIN-
	      STALLED"	environment  variable  keeps pkg-config from implicitly choosing "-uninstalled" packages, so if that variable is set, they
	      will only have been used if you pass a name like "foo-uninstalled" on the command line explicitly.)

       --exists

       --atleast-version=VERSION

       --exact-version=VERSION

       --max-version=VERSION
	      These options test whether the package or list of packages on the command line are known to pkg-config, and optionally  whether  the
	      version  number of a package meets certain contraints.  If all packages exist and meet the specified version constraints, pkg-config
	      exits successfully. Otherwise it exits unsuccessfully.

	      Rather than using the version-test options, you can simply give a version constraint after each package name, for example:
		$ pkg-config --exists 'glib-2.0 >= 1.3.4 libxml = 1.8.3'
	      Remember to use --print-errors if you want error messages.

       --msvc-syntax
	      This option is available only on Windows. It causes pkg-config to output -l and -L flags in the form  recognized	by  the  Microsoft
	      Visual  C++  command-line compiler, cl. Specifically, instead of -Lx:/some/path it prints /libpath:x/some/path, and instead of -lfoo
	      it prints foo.lib. Note that the --libs output consists of flags for the linker, and should be placed on the cl command line after a
	      /link switch.

       --dont-define-prefix
	      This  option  is	available  only on Windows. It prevents pkg-config from automatically trying to override the value of the variable
	      "prefix" in each .pc file.

       --prefix-variable=PREFIX
	      Also this option is available only on Windows. It sets the name of the variable that  pkg-config	automatically  sets  as  described
	      above.

       --static
	      Output libraries suitable for static linking.  That means including any private libraries in the output.	This relies on proper tag-
	      ging in the .pc files, else a too large number of libraries will ordinarily be output.

ENVIRONMENT VARIABLES

       PKG_CONFIG_PATH
	      A colon-separated (on Windows, semicolon-separated) list of directories to search for .pc files.	The default directory will  always
	      be  searched after searching the path; the default is libdir/pkgconfig:datadir/pkgconfig where libdir is the libdir where pkg-config
	      and datadir is the datadir where pkg-config was installed.

       PKG_CONFIG_DEBUG_SPEW
	      If set, causes pkg-config to print all kinds of debugging information and report all errors.

       PKG_CONFIG_TOP_BUILD_DIR
	      A value to set for the magic variable pc_top_builddir which may appear in .pc files. If the environment variable	is  not  set,  the
	      default  value '$(top_builddir)' will be used. This variable should refer to the top builddir of the Makefile where the compile/link
	      flags reported by pkg-config will be used.  This only matters  when  compiling/linking  against  a  package  that  hasn't  yet  been
	      installed.

       PKG_CONFIG_DISABLE_UNINSTALLED
	      Normally	if you request the package "foo" and the package "foo-uninstalled" exists, pkg-config will prefer the "-uninstalled" vari-
	      ant. This allows compilation/linking against uninstalled packages.  If this environment variable is set, it disables said behavior.

       PKG_CONFIG_ALLOW_SYSTEM_CFLAGS
	      Don't strip -I/usr/include out of cflags.

       PKG_CONFIG_ALLOW_SYSTEM_LIBS
	      Don't strip -L/usr/lib out of libs

       PKG_CONFIG_SYSROOT_DIR
	      Modify -I and -L to use the directories located in target sysroot.  this option is usefull when crosscompiling package that use pkg-
	      config  to  determine  CFLAGS  anf  LDFLAGS.  -I	and  -L  are  modified	to  point  to  the  new  system  root.	this  means that a
	      -I/usr/include/libfoo will become -I/var/target/usr/include/libfoo with a PKG_CONFIG_SYSROOT_DIR equal  to  /var/target  (same  rule
	      apply to -L)

       PKG_CONFIG_LIBDIR
	      Replaces the default pkg-config search directory.

WINDOWS SPECIALITIES

       If  a  .pc file is found in a directory that matches the usual conventions (i.e., ends with libpkgconfig), the prefix for that package is
       assumed to be the grandparent of the directory where the file was found, and the prefix variable is overridden for that file accordingly.

       In addition to the  PKG_CONFIG_PATH  environment  variable,  the  Registry  keys  HKEY_CURRENT_USERSoftwarepkgconfigPKG_CONFIG_PATH  and
       HKEY_LOCAL_MACHINESoftwarepkgconfigPKG_CONFIG_PATH  can  be  used to specify directories to search for .pc files. Each (string) value in
       these keys is treated as a directory where to look for .pc files.

AUTOCONF MACROS

       PKG_CHECK_MODULES(VARIABLE-PREFIX,MODULES[,ACTION-IF-FOUND,[ACTION-IF-NOT-FOUND]])

	      The macro PKG_CHECK_MODULES can be used in configure.ac to check whether modules exist. A typical usage would be:
	       PKG_CHECK_MODULES([MYSTUFF], [gtk+-2.0 >= 1.3.5 libxml = 1.8.4])

	      This would result in MYSTUFF_LIBS and MYSTUFF_CFLAGS substitution variables, set to the libs and cflags for the given  module  list.
	      If  a  module  is  missing  or has the wrong version, by default configure will abort with a message. To replace the default action,
	      specify an ACTION-IF-NOT-FOUND. PKG_CHECK_MODULES will not print any error messages if you  specify  your  own  ACTION-IF-NOT-FOUND.
	      However, it will set the variable MYSTUFF_PKG_ERRORS, which you can use to display what went wrong.

	      Note  that if there is a possibility the first call to PKG_CHECK_MODULES might not happen, you should be sure to include an explicit
	      call to PKG_PROG_PKG_CONFIG in your configure.ac

	      PKG_PROG_PKG_CONFIG([MIN-VERSION])

	      Defines the PKG_CONFIG variable to the best pkg-config available, useful if you need pkg-config but don't want to use PKG_CHECK_MOD-
	      ULES.

	      PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])

	      Check  to  see  whether  a  particular  set  of modules exists.  Similar to PKG_CHECK_MODULES(), but does not set variables or print
	      errors.

	      Similar to PKG_CHECK_MODULES, make sure that the first instance of this or  PKG_CHECK_MODULES  is  called,  or  make  sure  to  call
	      PKG_CHECK_EXISTS manually

METADATA FILE SYNTAX

       To  add	a library to the set of packages pkg-config knows about, simply install a .pc file. You should install this file to libdir/pkgcon-
       fig.

       Here is an example file:
       # This is a comment
       prefix=/home/hp/unst   # this defines a variable
       exec_prefix=${prefix}  # defining another variable in terms of the first
       libdir=${exec_prefix}/lib
       includedir=${prefix}/include

       Name: GObject				# human-readable name
       Description: Object/type system for GLib # human-readable description
       Version: 1.3.1
       URL: http://www.gtk.org
       Requires: glib-2.0 = 1.3.1
       Conflicts: foobar <= 4.5
       Libs: -L${libdir} -lgobject-1.3
       Libs.private: -lm
       Cflags: -I${includedir}/glib-2.0 -I${libdir}/glib/include

       You would normally generate the file using configure, of course, so that the prefix, etc. are set to the proper values.

       Files have two kinds of line: keyword lines start with a keyword plus a colon, and variable definitions start with an  alphanumeric  string
       plus  an  equals sign. Keywords are defined in advance and have special meaning to pkg-config; variables do not, you can have any variables
       that you wish (however, users may expect to retrieve the usual directory name variables).

       Note that variable references are written "${foo}"; you can escape literal "${" as "$${".

       Name:  This field should be a human-readable name for the package. Note that it is not the name passed as an argument to pkg-config.

       Description:
	      This should be a brief description of the package

       URL:   An URL where people can get more information about and download the package

       Version:
	      This should be the most-specific-possible package version string.

       Requires:
	      This is a comma-separated list of packages that are required by your package. Flags from dependent packages will be merged in to the
	      flags  reported  for your package. Optionally, you can specify the version of the required package (using the operators =, <, >, >=,
	      <=); specifying a version allows pkg-config to perform extra sanity checks. You may only mention the same package one  time  on  the
	      Requires: line. If the version of a package is unspecified, any version will be used with no checking.

       Conflicts:
	      This optional line allows pkg-config to perform additional sanity checks, primarily to detect broken user installations.	The syntax
	      is the same as Requires: except that you can list the same package more than once here, for example "foobar = 1.2.3, foobar = 1.2.5,
	      foobar >= 1.3", if you have reason to do so. If a version isn't specified, then your package conflicts with all versions of the men-
	      tioned package.  If a user tries to use your package and a conflicting package at the same time, then pkg-config will complain.

       Libs:  This line should give the link flags specific to your package.  Don't add any flags for required packages; pkg-config will add those
	      automatically.

       Libs.private:
	      This line should list any private libraries in use.  Private libraries are libraries which are not exposed through your library, but
	      are needed in the case of static linking.

       Cflags:
	      This line should list the compile flags specific to your package.  Don't add any flags for required packages;  pkg-config  will  add
	      those automatically.

AUTHOR

       pkg-config  was	written by James Henstridge, rewritten by Martijn van Beers, and rewritten again by Havoc Pennington. Tim Janik, Owen Tay-
       lor, and Raja Harinath submitted suggestions and some code.  gnome-config was written by Miguel de Icaza, Raja Harinath and various hackers
       in the GNOME team.  It was inspired by Owen Taylor's gtk-config program.

BUGS

       pkg-config does not handle mixing of parameters with and without = well.  Stick with one.

																     pkg-config(1)