5.11 Makefile Options

Some large applications can be built in a number of configurations, adding functionality if one of a number of libraries or applications is available. Examples include choice of natural (human) language, GUI versus command-line, or type of database to support. Since not all users want those libraries or applications, the ports system provides hooks that the port author can use to control which configuration should be built. Supporting these properly will make users happy, and effectively provide 2 or more ports for the price of one.

5.11.1 Knobs WITH_* and WITHOUT_*

These variables are designed to be set by the system administrator. There are many that are standardized in ports/KNOBS file.

When creating a port, do not make knob names specific to a given application. For example in Avahi port, use WITHOUT_MDNS instead of WITHOUT_AVAHI_MDNS.

Note: You should not assume that a WITH_* necessarily has a corresponding WITHOUT_* variable and vice versa. In general, the default is simply assumed.

Note: Unless otherwise specified, these variables are only tested for being set or not set, rather than being set to some kind of variable such as YES or NO.

Table 5-3. Common WITH_* and WITHOUT_* Variables

Variable Means
WITHOUT_NLS If set, says that internationalization is not needed, which can save compile time. By default, internationalization is used.
WITH_OPENSSL_BASE Use the version of OpenSSL in the base system.
WITH_OPENSSL_PORT Installs the version of OpenSSL from security/openssl, even if the base is up to date.
WITHOUT_X11 If the port can be built both with and without X support, then it should normally be built with X support. If this variable is defined, then the version that does not have X support should be built instead. Knob Naming

It is recommended that porters use like-named knobs, for the benefit of end-users and to help keep the number of knob names down. A list of popular knob names can be found in the KNOBS file.

Knob names should reflect what the knob is and does. When a port has a lib-prefix in the PORTNAME the lib-prefix should be dropped in knob naming.

5.11.2 OPTIONS Background

The OPTIONS_* variables give the user who installs the port a dialog with the available options and saves them to /var/db/ports/${UNIQUENAME}/options. Next time when the port has to be rebuilt, the options are reused.

When the user runs make config (or runs make build for the first time), the framework will check for /var/db/ports/${UNIQUENAME}/options. If that file does not exist, it will use the values of OPTIONS_* to create a dialog box where the options can be enabled or disabled. Then the options file is saved and the selected variables will be used when building the port.

If a new version of the port adds new OPTIONS, the dialog will be presented to the user, with the saved values of old OPTIONS prefilled.

Use make showconfig to see the saved configuration. Use make rmconfig to remove the saved configuration. Syntax

OPTIONS_DEFINE contains a list of OPTIONS to be used. These are independent of each other and are not grouped:


Once defined, OPTIONS are optionally described:

OPT1_DESC=	Describe OPT1
OPT2_DESC=	Describe OPT2
OPT3_DESC=	Describe OPT3
OPT4_DESC=	Describe OPT4
OPT5_DESC=	Describe OPT5
OPT6_DESC=	Describe OPT6

Tip: ports/Mk/bsd.options.desc.mk has descriptions for many common OPTIONS; there is usually no need to override these.

OPTIONS can be grouped as radio choices (only one choice from each group allowed):


OPTIONS can also be grouped as ``multiple-choice'' lists, where at least one option must be enabled:


OPTIONS are unset by default, unless they are listed in OPTIONS_DEFAULT:


OPTIONS definitions must appear before the inclusion of bsd.port.options.mk. The PORT_OPTIONS variable can only be tested after the inclusion of bsd.port.options.mk. Inclusion of bsd.port.pre.mk can be used instead, too, and is still widely used in ports written before the introduction of bsd.port.options.mk. But be aware that some variables will not work as expected after the inclusion of bsd.port.pre.mk, typically some USE_* flags.

Example 5-10. Simple Use of OPTIONS

FOO_DESC=	Enable option foo
BAR_DESC=	Support feature bar


.include <bsd.port.options.mk>


RUN_DEPENDS+=	bar:${PORTSDIR}/bar/bar

.include <bsd.port.mk>

Example 5-11. Practical Use of OPTIONS




EXAMPLES_DESC=		Install extra examples
MYSQL_DESC=		Use MySQL as backend
PGSQL_DESC=		Use PostgreSQL as backend
BDB_DESC=		Use Berkeley DB as backend
LDAP_DESC=		Build with LDAP authentication support
PAM_DESC=		Build with PAM support
SSL_DESC=		Build with OpenSSL support


.include <bsd.port.options.mk>

CONFIGURE_ARGS+=	--with-postgres
CONFIGURE_ARGS+=	--without-postgres

LIB_DEPENDS+=	icuuc:${PORTSDIR}/devel/icu

# Check other OPTIONS

.include <bsd.port.mk>

Example 5-12. Old-Style Use of OPTIONS

OPTIONS=	FOO "Enable option foo" On

.include <bsd.port.pre.mk>

.if defined(WITHOUT_FOO)
CONFIGURE_ARGS+=	--without-foo
CONFIGURE_ARGS+=	--with-foo

.include <bsd.port.post.mk>

Important: This method of using OPTIONS is deprecated, and will be removed at some point. It should not be included in new ports.

5.11.3 Feature Auto-Activation

When using a GNU configure script, keep an eye on which optional features are activated by auto-detection. Explicitly disable optional features you do not wish to be used by passing respective --without-xxx or --disable-xxx in CONFIGURE_ARGS.

Example 5-13. Wrong Handling of an Option

LIB_DEPENDS+=		foo.0:${PORTSDIR}/devel/foo
CONFIGURE_ARGS+=	--enable-foo

In the example above, imagine a library libfoo is installed on the system. User does not want this application to use libfoo, so he toggled the option off in the make config dialog. But the application's configure script detects the library present in the system and includes its support in the resulting executable. Now when user decides to remove libfoo from the system, the ports system does not protest (no dependency on libfoo was recorded) but the application breaks.

Example 5-14. Correct Handling of an Option

LIB_DEPENDS+=		foo.0:${PORTSDIR}/devel/foo
CONFIGURE_ARGS+=	--enable-foo
CONFIGURE_ARGS+=	--disable-foo

In the second example, the library libfoo is explicitly disabled. The configure script does not enable related features in the application, despite library's presence in the system.

For questions about the FreeBSD ports system, e-mail <ports@FreeBSD.org>.
For questions about this documentation, e-mail <doc@FreeBSD.org>.