Provided by: pkg-config_0.26-1ubuntu1_amd64 bug

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]    [--print-variables]   [--uninstalled]   [--exists]
       [--atleast-version=VERSION] [--exact-version=VERSION] [--max-version=VERSION] [--list-all]
       [LIBRARIES...]      [--print-provides]    [--print-requires]    [--print-requires-private]
       [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, and has a .pc extension.  On most systems, pkg-config looks
       in     /usr/lib/pkgconfig,     /usr/share/pkgconfig,     /usr/local/lib/pkgconfig      and
       /usr/local/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.

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.

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

       --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

       --print-variables
              Returns a list of all variables defined in the package.

       --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
              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  constraints.   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 tagging in the .pc  files,  else  a
              too large number of libraries will ordinarily be output.

       --list-all
              List all modules found in the pkg-config path.

       -I "--print-provides"
              List all modules the given packages provides.

       --print-requires
              List all modules the given packages requires.

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

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
              for pkg-config and datadir is the datadir for pkg-config when it 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
              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/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, usually /usr/lib/pkgconfig

QUERYING PKG-CONFIG'S DEFAULTS

       pkg-config can be used to query itself for the default search  path,  version  number  and
       other information, for instance using:
         $ pkg-config --variable pc_path pkg-config
       or
         $ pkg-config --modversion pkg-config

WINDOWS SPECIALITIES

       If  a .pc file is found in a directory that matches the usual conventions (i.e., ends with
       \lib\pkgconfig or \share\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 original,  non-overridden,  value
       of the prefix variable, then the overridden value of prefix is used instead.

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_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/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, so that the prefix, etc. are set to
       the proper values.  The GNU Autoconf manual recommends generating files like .pc files  at
       build time rather than configure time, so when you build the .pc file is a matter of taste
       and preference.

       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.

       Requires.private:
              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  dynamically 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 dependencies between the
              libraries.

       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. This differs from Requires.private in that it references libraries
              that do not have package files installed.

       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.

       Bugs can be reported at http://bugs.freedesktop.org/ under the pkg-config component.

                                                                                    pkg-config(1)