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

       pkg-config - Return metainformation about installed libraries

       pkg-config  [--modversion]  [--version]  [--help] [--atleast-pkgconfig-
       version=VERSION] [--print-errors]  [--short-errors]  [--silence-errors]
       [--errors-to-stdout]   [--debug]  [--cflags]  [--libs]  [--libs-only-L]
       [--libs-only-l] [--cflags-only-I]  [--libs-only-other]  [--cflags-only-
       other]  [--variable=VARIABLENAME] [--define-variable=VARIABLENAME=VARI-
       ABLEVALUE] [--print-variables] [--uninstalled]  [--exists]  [--atleast-
       version=VERSION]    [--exact-version=VERSION]   [--max-version=VERSION]
       [--validate]   [--list-all]    [--print-provides]    [--print-requires]
       [--print-requires-private] [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, and has a .pc exten-
       sion.   On  most  systems,  pkg-config  looks  in   /usr/lib/pkgconfig,
       /usr/share/pkgconfig,     /usr/local/lib/pkgconfig     and     /usr/lo-
       cal/share/pkgconfig for these files.  It will additionally 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 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").

       In addition to specifying a package name on the command line, the  full
       path  to  a  given .pc file may be given instead. This allows a user to
       directly query a particular .pc file.

       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.

              Displays the version of pkg-config and terminates.

              Requires at least the given version of pkg-config.

       --help Displays a help message and terminates.

              If one or more of the modules on the command line, or their  de-
              pendencies,  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 "--ex-
              ists" 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_CON-
              FIG_DEBUG_SPEW environment variable overrides this option.

              Print short error messages.

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

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

              Print debugging information. This is slightly different than the
              PKG_CONFIG_DEBUG_SPEW environment variable,  which  also  enable

       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.

              This prints the -I part of "--cflags". That is, it  defines  the
              header search path but doesn't specify anything else.

              This  prints  parts of "--cflags" not covered by "--cflags-only-

       --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 prints the parts of "--libs" not covered by "--libs-only-L"
              and "--libs-only-l", such as "--pthread".

              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

              Returns a list of all variables defined in the package.

              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 be-
              ing used, and return failure (false) otherwise.   (The  PKG_CON-
              FIG_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  constraints.   If
              all  packages  exist and meet the specified version constraints,
              pkg-config exits successfully.  Otherwise  it  exits  unsuccess-
              fully.  Only the first VERSION comparing option will be honored.
              Subsequent options of this type will be ignored.

              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. When
              no output options are supplied to pkg-config,  --exists  is  im-

              Checks  the syntax of a package's .pc file for validity. This is
              the same as --exists except that dependencies are not  verified.
              This can be useful for package developers to test their .pc file
              prior to release:
                $ pkg-config --validate ./my-package.pc

              This option is available only on Windows. It  causes  pkg-config
              to  output  -l and -L flags in the form recognized by the Micro-
              soft 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.

              These options control whether pkg-config overrides the value  of
              the variable prefix in each .pc file. With --define-prefix, pkg-
              config uses the installed location of the .pc file to  determine
              the prefix. --dont-define-prefix prevents this behavior. The de-
              fault is usually --define-prefix.

              When this feature is enabled and a .pc file is found in a direc-
              tory  named 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.

              If  the value of a variable in a .pc file begins with the origi-
              nal, non-overridden, value of  the  prefix  variable,  then  the
              overridden value of prefix is used instead. This allows the fea-
              ture to work even when the variables have been expanded  in  the
              .pc file.

              Set  the  name of the variable that pkg-config overrides instead
              of prefix when using the --define-prefix feature.

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

              List all modules found in the pkg-config path.

              List all modules the given packages provides.

              List all modules the given packages requires.

              List  all modules the given packages requires for static linking
              (see --static).

              A colon-separated (on Windows, semicolon-separated) list of  di-
              rectories  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
              for pkg-config and datadir is the datadir for pkg-config when it
              was installed.

              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 or -L/lib out of libs.

              Modify -I and -L to use the directories located in  target  sys-
              root.   this option is useful when cross-compiling packages that
              use pkg-config to determine CFLAGS and 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,   usually

              Overrides  the variable VARIABLE in the package PACKAGE. The en-
              vironment variable should have  the  package  name  and  package
              variable  upper cased with non-alphanumeric characters converted
              to underscores. For example, setting PKG_CONFIG_GLADEUI_2_0_CAT-
              ALOGDIR   will   override   the  variable  "catalogdir"  in  the
              "gladeui-2.0" package.

       pkg-config sets a few metadata variables that can be used in .pc  files
       or queried at runtime.

              The  default  search  path used by pkg-config when searching for
              .pc files. This can be used in a query for the pkg-config module
              itself itself:
                $ pkg-config --variable pc_path pkg-config

              The  installed  location  of  the  .pc file. This can be used to
              query the location of the .pc file for a particular module,  but
              it can also be used to make .pc files relocatable. For instance:

              The  sysroot  directory set by the user. When the sysroot direc-
              tory has not been set, this value is /.  See the PKG_CONFIG_SYS-
              ROOT_DIR environment variable for more details.

              Location of the user's top build directory when calling pkg-con-
              fig.  This is useful to dynamically set paths in uninstalled .pc
              files. See the PKG_CONFIG_TOP_BUILD_DIR environment variable for
              more details.

       The pkg-config default search path is ignored on Windows. Instead,  the
       search path is constructed by using the installed directory of pkg-con-
       fig and then appending lib\pkgconfig and share\pkgconfig.  This can  be
       augmented  or  replaced  using  the  standard environment variables de-
       scribed above.


              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  de-
              fault  configure  will  abort with a message. To replace the de-
              fault action, specify an ACTION-IF-NOT-FOUND.  PKG_CHECK_MODULES
              will  not  print  any error messages if you specify your own AC-
              TION-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 in-
              clude an explicit call to PKG_PROG_PKG_CONFIG  in  your  config-

              Also  note  that repeated usage of VARIABLE-PREFIX is not recom-
              mended.  After the first successful usage, subsequent calls with
              the  same  VARIABLE-PREFIX will simply use the _LIBS and _CFLAGS
              variables set from the previous usage without calling pkg-config

              Checks that the version of the pkg-config autoconf macros in use
              is at least MIN-VERSION. This can be used to ensure a particular
              pkg-config macro will be available.


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

              Enables  static  linking  through  --static  prior  to   calling


              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.


              Substitutes  the  variable  pkgconfigdir as the location where a
              module should install pkg-config .pc files. By default  the  di-
              rectory  is $libdir/pkgconfig, but the default can be changed by
              passing DIRECTORY.  The user can override  through  the  --with-
              pkgconfigdir parameter.


              Substitutes  the  variable  noarch_pkgconfigdir  as the location
              where a module should install  arch-independent  pkg-config  .pc
              files.  By  default the directory is $datadir/pkgconfig, but the
              default can be changed by passing DIRECTORY. The user can  over-
              ride through the --with-noarch-pkgconfigdir parameter.


              Retrieves the value of the pkg-config  variable  CONFIG-VARIABLE
              from  MODULE and stores it in VARIABLE. Note that repeated usage
              of VARIABLE is not recommended as the check will be  skipped  if
              the variable is already set.

       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, so that the  pre-
       fix, etc. are set to the proper values.  The GNU Autoconf manual recom-
       mends generating files like .pc files at build time rather than config-
       ure time, so when you build the .pc file is a matter of taste and pref-

       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 un-
              specified, any version will be used with no checking.

              A list of packages required by this package. The difference from
              Requires  is that the packages listed under Requires.private are
              not taken into account when a flag list is computed for  dynami-
              cally linked executable (i.e., when --static was not specified).
              In the situation where each .pc file corresponds to  a  library,
              Requires.private shall be used exclusively to specify the depen-
              dencies between the libraries.

              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 li-
              braries  are  libraries  which  are not exposed through your li-
              brary, but are needed in the case of static linking.  This  dif-
              fers  from Requires.private in that it references libraries that
              do not have package files installed.

              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.

       Bugs can be reported at under the pkg-con-
       fig component.

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