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X11R7.4 - man page for pkg-config (x11r4 section 1)

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pkg-config(1)									    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=VER-
       SION] [--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  Windows,  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 simul-
       taneously, 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 undefined.

       --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-config 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 variable 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" variant. 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_UNINSTALLED" environment vari-
	      able 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-unin-
	      stalled" 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  con-
	      straints, pkg-config exits successfully. Otherwise it exits unsuccessfully.

	      Rather  than  using  the	version-test  options, you can simply give a version con-
	      straint 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 tagging 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" variant. 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_CON-
	      FIG_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
       \lib\pkgconfig), 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_CUR-
       RENT_USER\Software\pkgconfig\PKG_CONFIG_PATH    and    HKEY_LOCAL_MACHINE\Software\pkgcon-
       fig\PKG_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_MODULES.

	      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_MOD-
	      ULES(), 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/pkgconfig.

       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  vari-
       able  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 opera-
	      tors =, <, >, >=, <=); specifying a version allows pkg-config to perform extra san-
	      ity  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 check-
	      ing.

       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 mentioned
	      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 Taylor, 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)
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