1pkg-config(1) General Commands Manual pkg-config(1)
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6 pkg-config - Return metainformation about installed libraries
7
9 pkg-config [--modversion] [--help] [--print-errors] [--silence-errors]
10 [--cflags] [--libs] [--libs-only-L] [--libs-only-l] [--cflags-only-I]
11 [--variable=VARIABLENAME] [--define-variable=VARIABLENAME=VARIABLE‐
12 VALUE] [--print-variables] [--uninstalled] [--exists] [--atleast-ver‐
13 sion=VERSION] [--exact-version=VERSION] [--max-version=VERSION]
14 [--list-all] [LIBRARIES...] [--print-provides] [--print-requires]
15 [--print-requires-private] [LIBRARIES...]
16
18 The pkg-config program is used to retrieve information about installed
19 libraries in the system. It is typically used to compile and link
20 against one or more libraries. Here is a typical usage scenario in a
21 Makefile:
22 program: program.c
24 cc program.c $(pkg-config --cflags --libs gnomeui)
25 pkg-config retrieves information about packages from special metadata
27 files. These files are named after the package, and has a .pc exten‐
28 sion. On most systems, pkg-config looks in and
29 for these files. It will additionally look in the colon-separated (on
30 Windows, semicolon-separated) list of directories specified by the
31 PKG_CONFIG_PATH environment variable.
32 The package name specified on the pkg-config command line is defined to
34 be the name of the metadata file, minus the .pc extension. If a library
35 can install multiple versions simultaneously, it must give each version
36 its own name (for example, GTK 1.2 might have the package name "gtk+"
37 while GTK 2.0 has "gtk+-2.0").
38
40 The following options are supported:
41 --modversion
43 Requests that the version information of the libraries specified
44 on the command line be displayed. If pkg-config can find all
45 the libraries on the command line, each library's version string
46 is printed to stdout, one version per line. In this case pkg-
47 config exits successfully. If one or more libraries is unknown,
48 pkg-config exits with a nonzero code, and the contents of stdout
49 are undefined.
50 --help Displays a help message and terminates.
52 --print-errors
54 If one or more of the modules on the command line, or their
55 dependencies, are not found, or if an error occurs in parsing a
56 .pc file, then this option will cause errors explaining the
57 problem to be printed. With "predicate" options such as
58 "--exists" pkg-config runs silently by default, because it's
59 usually used in scripts that want to control what's output. This
60 option can be used alone (to just print errors encountered
61 locating modules on the command line) or with other options. The
62 PKG_CONFIG_DEBUG_SPEW environment variable overrides this
63 option.
64 --silence-errors
66 If one or more of the modules on the command line, or their
67 dependencies, are not found, or if an error occurs in parsing a
68 a .pc file, then this option will keep errors explaining the
69 problem from being printed. With "predicate" options such as
70 "--exists" pkg-config runs silently by default, because it's
71 usually used in scripts that want to control what's output. So
72 this option is only useful with options such as "--cflags" or
73 "--modversion" that print errors by default. The PKG_CON‐
74 FIG_DEBUG_SPEW environment variable overrides this option.
75 --errors-to-stdout
77 If printing errors, print them to stdout rather than the default
78 stderr
79 The following options are used to compile and link programs:
82 --cflags
84 This prints pre-processor and compile flags required to compile
85 the packages on the command line, including flags for all their
86 dependencies. Flags are "compressed" so that each identical flag
87 appears only once. pkg-config exits with a nonzero code if it
88 can't find metadata for one or more of the packages on the com‐
89 mand line.
90 --cflags-only-I
92 This prints the -I part of "--cflags". That is, it defines the
93 header search path but doesn't specify anything else.
94 --libs This option is identical to "--cflags", only it prints the link
96 flags. As with "--cflags", duplicate flags are merged (maintain‐
97 ing proper ordering), and flags for dependencies are included in
98 the output.
99 --libs-only-L
101 This prints the -L/-R part of "--libs". That is, it defines the
102 library search path but doesn't specify which libraries to link
103 with.
104 --libs-only-l
106 This prints the -l part of "--libs" for the libraries specified
107 on the command line. Note that the union of "--libs-only-l" and
108 "--libs-only-L" may be smaller than "--libs", due to flags such
109 as -rdynamic.
110 --variable=VARIABLENAME
112 This returns the value of a variable defined in a package's .pc
113 file. Most packages define the variable "prefix", for example,
114 so you can say:
115 $ pkg-config --variable=prefix glib-2.0
116 /usr/
117 --define-variable=VARIABLENAME=VARIABLEVALUE
119 This sets a global value for a variable, overriding the value in
120 any files. Most packages define the variable "prefix", for exam‐
121 ple, so you can say:
122 $ pkg-config --print-errors --define-variable=prefix=/foo \
123 --variable=prefix glib-2.0
124 /foo
125 --print-variables
127 Returns a list of all variables defined in the package.
128 --uninstalled
131 Normally if you request the package "foo" and the package "foo-
132 uninstalled" exists, pkg-config will prefer the "-uninstalled"
133 variant. This allows compilation/linking against uninstalled
134 packages. If you specify the "--uninstalled" option, pkg-config
135 will return successfully if any "-uninstalled" packages are
136 being used, and return failure (false) otherwise. (The PKG_CON‐
137 FIG_DISABLE_UNINSTALLED environment variable keeps pkg-config
138 from implicitly choosing "-uninstalled" packages, so if that
139 variable is set, they will only have been used if you pass a
140 name like "foo-uninstalled" on the command line explicitly.)
141 --exists
143 --atleast-version=VERSION
145 --exact-version=VERSION
147 --max-version=VERSION
149 These options test whether the package or list of packages on
150 the command line are known to pkg-config, and optionally whether
151 the version number of a package meets certain contraints. If
152 all packages exist and meet the specified version constraints,
153 pkg-config exits successfully. Otherwise it exits unsuccess‐
154 fully.
155 Rather than using the version-test options, you can simply give
157 a version constraint after each package name, for example:
158 $ pkg-config --exists 'glib-2.0 >= 1.3.4 libxml = 1.8.3'
159 Remember to use --print-errors if you want error messages.
160 --msvc-syntax
162 This option is available only on Windows. It causes pkg-config
163 to output -l and -L flags in the form recognized by the Micro‐
164 soft Visual C++ command-line compiler, cl. Specifically, instead
165 of it prints /libpath:x/some/path, and instead of -lfoo it
166 prints foo.lib. Note that the --libs output consists of flags
167 for the linker, and should be placed on the cl command line
168 after a /link switch.
169 --dont-define-prefix
171 This option is available only on Windows. It prevents pkg-config
172 from automatically trying to override the value of the variable
173 "prefix" in each .pc file.
174 --prefix-variable=PREFIX
176 Also this option is available only on Windows. It sets the name
177 of the variable that pkg-config automatically sets as described
178 above.
179 --static
181 Output libraries suitable for static linking. That means
182 including any private libraries in the output. This relies on
183 proper tagging in the .pc files, else a too large number of
184 libraries will ordinarily be output.
185 --list-all
187 List all modules found in the pkg-config path.
188 -I "--print-provides"
190 List all modules the given packages provides.
191 --print-requires
193 List all modules the given packages requires.
194 --print-requires-private
196 List all modules the given packages requires for static linking
197 (see --static).
198
200 PKG_CONFIG_PATH
201 A colon-separated (on Windows, semicolon-separated) list of
202 directories to search for .pc files. The default directory will
203 always be searched after searching the path; the default is
204 libdir/pkgconfig:datadir/pkgconfig where libdir is the libdir
205 for pkg-config and datadir is the datadir for pkg-config when it
206 was installed.
207 PKG_CONFIG_DEBUG_SPEW
209 If set, causes pkg-config to print all kinds of debugging infor‐
210 mation and report all errors.
211 PKG_CONFIG_TOP_BUILD_DIR
213 A value to set for the magic variable pc_top_builddir which may
214 appear in .pc files. If the environment variable is not set, the
215 default value '$(top_builddir)' will be used. This variable
216 should refer to the top builddir of the Makefile where the com‐
217 pile/link flags reported by pkg-config will be used. This only
218 matters when compiling/linking against a package that hasn't yet
219 been installed.
220 PKG_CONFIG_DISABLE_UNINSTALLED
222 Normally if you request the package "foo" and the package "foo-
223 uninstalled" exists, pkg-config will prefer the "-uninstalled"
224 variant. This allows compilation/linking against uninstalled
225 packages. If this environment variable is set, it disables said
226 behavior.
227 PKG_CONFIG_ALLOW_SYSTEM_CFLAGS
229 Don't strip -I/usr/include out of cflags.
230 PKG_CONFIG_ALLOW_SYSTEM_LIBS
232 Don't strip -L/usr/lib out of libs
233 PKG_CONFIG_SYSROOT_DIR
235 Modify -I and -L to use the directories located in target sys‐
236 root. this option is useful when crosscompiling package that
237 use pkg-config to determine CFLAGS anf LDFLAGS. -I and -L are
238 modified to point to the new system root. this means that a
239 -I/usr/include/libfoo will become -I/var/target/usr/include/lib‐
240 foo with a PKG_CONFIG_SYSROOT_DIR equal to /var/target (same
241 rule apply to -L)
242 PKG_CONFIG_LIBDIR
244 Replaces the default pkg-config search directory, usually
245 /usr/lib/pkgconfig
246
248 pkg-config can be used to query itself for the default search path,
249 version number and other information, for instance using:
250 $ pkg-config --variable pc_path pkg-config
251 or
252 $ pkg-config --modversion pkg-config
253
255 If a .pc file is found in a directory that matches the usual conven‐
256 tions (i.e., ends with \lib\pkgconfig or \share\pkgconfig), the prefix
257 for that package is assumed to be the grandparent of the directory
258 where the file was found, and the prefix variable is overridden for
259 that file accordingly.
260 If the value of a variable in a .pc file begins with the original, non-
262 overridden, value of the prefix variable, then the overridden value of
263 prefix is used instead.
264
266 PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES [,ACTION-IF-FOUND [,ACTION-
267 IF-NOT-FOUND]])
268 The macro PKG_CHECK_MODULES can be used in configure.ac to check
270 whether modules exist. A typical usage would be:
271 PKG_CHECK_MODULES([MYSTUFF], [gtk+-2.0 >= 1.3.5 libxml = 1.8.4])
272 This would result in MYSTUFF_LIBS and MYSTUFF_CFLAGS substitu‐
274 tion variables, set to the libs and cflags for the given module
275 list. If a module is missing or has the wrong version, by
276 default configure will abort with a message. To replace the
277 default action, specify an ACTION-IF-NOT-FOUND.
278 PKG_CHECK_MODULES will not print any error messages if you spec‐
279 ify your own ACTION-IF-NOT-FOUND. However, it will set the
280 variable MYSTUFF_PKG_ERRORS, which you can use to display what
281 went wrong.
282 Note that if there is a possibility the first call to
284 PKG_CHECK_MODULES might not happen, you should be sure to
285 include an explicit call to PKG_PROG_PKG_CONFIG in your config‐
286 ure.ac.
287 PKG_PROG_PKG_CONFIG([MIN-VERSION])
289 Defines the PKG_CONFIG variable to the best pkg-config avail‐
291 able, useful if you need pkg-config but don't want to use
292 PKG_CHECK_MODULES.
293 PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
295 Check to see whether a particular set of modules exists. Simi‐
297 lar to PKG_CHECK_MODULES(), but does not set variables or print
298 errors.
299 Similar to PKG_CHECK_MODULES, make sure that the first instance
301 of this or PKG_CHECK_MODULES is called, or make sure to call
302 PKG_CHECK_EXISTS manually.
303
306 To add a library to the set of packages pkg-config knows about, simply
307 install a .pc file. You should install this file to libdir/pkgconfig.
308 Here is an example file:
310 # This is a comment
311 prefix=/home/hp/unst # this defines a variable
312 exec_prefix=${prefix} # defining another variable in terms of the first
313 libdir=${exec_prefix}/lib
314 includedir=${prefix}/include
315 Name: GObject # human-readable name
317 Description: Object/type system for GLib # human-readable description
318 Version: 1.3.1
319 URL: http://www.gtk.org
320 Requires: glib-2.0 = 1.3.1
321 Conflicts: foobar <= 4.5
322 Libs: -L${libdir} -lgobject-1.3
323 Libs.private: -lm
324 Cflags: -I${includedir}/glib-2.0 -I${libdir}/glib/include
325 You would normally generate the file using configure, of course, so
327 that the prefix, etc. are set to the proper values.
328 Files have two kinds of line: keyword lines start with a keyword plus a
330 colon, and variable definitions start with an alphanumeric string plus
331 an equals sign. Keywords are defined in advance and have special mean‐
332 ing to pkg-config; variables do not, you can have any variables that
333 you wish (however, users may expect to retrieve the usual directory
334 name variables).
335 Note that variable references are written "${foo}"; you can escape lit‐
337 eral "${" as "$${".
338 Name: This field should be a human-readable name for the package. Note
340 that it is not the name passed as an argument to pkg-config.
341 Description:
343 This should be a brief description of the package
344 URL: An URL where people can get more information about and download
346 the package
347 Version:
349 This should be the most-specific-possible package version
350 string.
351 Requires:
353 This is a comma-separated list of packages that are required by
354 your package. Flags from dependent packages will be merged in to
355 the flags reported for your package. Optionally, you can specify
356 the version of the required package (using the operators =, <,
357 >, >=, <=); specifying a version allows pkg-config to perform
358 extra sanity checks. You may only mention the same package one
359 time on the Requires: line. If the version of a package is
360 unspecified, any version will be used with no checking.
361 Requires.private:
363 A list of packages required by this package. The difference from
364 Requires is that the packages listed under Requires.private are
365 not taken into account when a flag list is computed for dynami‐
366 cally linked executable (i.e., when --static was not specified).
367 In the situation where each .pc file corresponds to a library,
368 Requires.private shall be used exclusively to specify the depen‐
369 dencies between the libraries.
370 Conflicts:
372 This optional line allows pkg-config to perform additional san‐
373 ity checks, primarily to detect broken user installations. The
374 syntax is the same as Requires: except that you can list the
375 same package more than once here, for example "foobar = 1.2.3,
376 foobar = 1.2.5, foobar >= 1.3", if you have reason to do so. If
377 a version isn't specified, then your package conflicts with all
378 versions of the mentioned package. If a user tries to use your
379 package and a conflicting package at the same time, then pkg-
380 config will complain.
381 Libs: This line should give the link flags specific to your package.
383 Don't add any flags for required packages; pkg-config will add
384 those automatically.
385 Libs.private:
387 This line should list any private libraries in use. Private
388 libraries are libraries which are not exposed through your
389 library, but are needed in the case of static linking. This dif‐
390 fers from Requires.private in that it references libraries that
391 do not have package files installed.
392 Cflags:
394 This line should list the compile flags specific to your pack‐
395 age. Don't add any flags for required packages; pkg-config will
396 add those automatically.
397
399 pkg-config was written by James Henstridge, rewritten by Martijn van
400 Beers, and rewritten again by Havoc Pennington. Tim Janik, Owen Taylor,
401 and Raja Harinath submitted suggestions and some code. gnome-config
402 was written by Miguel de Icaza, Raja Harinath and various hackers in
403 the GNOME team. It was inspired by Owen Taylor's gtk-config program.
404
406 pkg-config does not handle mixing of parameters with and without =
407 well. Stick with one.
408 Bugs can be reported at http://bugs.freedesktop.org/ under the pkg-con‐
410 fig component.
411 pkg-config(1)