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pkg-config(1)							 pkg-config(1)

       pkg-config - Return metainformation about installed libraries

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

       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

       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_CON-
       FIG_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").

       The following options are supported:

	      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.

	      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

	      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_CON-
	      FIG_DEBUG_SPEW environment variable overrides this option.

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

       The following options are used to compile and link programs:

	      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 com-
	      mand line.

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

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

	      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.

	      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

	      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

	      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 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.)




	      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 unsuccess-

	      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.

	      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.

	      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.

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

	      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.

	      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 lib-
	      dir/pkgconfig:datadir/pkgconfig where libdir is the libdir where
	      pkg-config and datadir  is  the  datadir	where  pkg-config  was

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

	      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 com-
	      pile/link	flags reported by pkg-config will be used.  This  only
	      matters when compiling/linking against a package that hasn't yet
	      been installed.

	      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

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

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

	      Modify -I	and -L to use the directories located in  target  sys-
	      root.   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/lib-
	      foo  with	 a  PKG_CONFIG_SYSROOT_DIR  equal to /var/target (same
	      rule apply to -L)

	      Replaces the default pkg-config search directory.

       If a .pc	file is	found in a directory that matches  the	usual  conven-
       tions  (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_CURRENT_USER\Software\pkgconfig\PKG_CONFIG_PATH	   and
       HKEY_LOCAL_MACHINE\Software\pkgconfig\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.


	      The macro	PKG_CHECK_MODULES can be used in 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 substitu-
	      tion 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_MOD-
	      ULES 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

	      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 config-


	      Defines the PKG_CONFIG variable to the  best  pkg-config	avail-
	      able,  useful  if	 you  need  pkg-config	but  don't want	to use


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

	      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

       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

       Name: GObject				# human-readable name
       Description: Object/type	system for GLib	# human-readable description
       Version:	1.3.1
       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 mean-
       ing 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 "${foo}"; you can escape lit-
       eral "${" 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.

	      This should be a brief description of the	package

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

	      This   should  be	 the  most-specific-possible  package  version

	      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.

	      This  optional line allows pkg-config to perform additional san-
	      ity 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.

	      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.

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

       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.

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



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