5.12 Makefile Options

Many applications can be built with optional or differing configurations. Examples include choice of natural (human) language, GUI versus command-line, or type of database to support. Users may need a different configuration than the default, so the ports system provides hooks the port author can use to control which variant will be built. Supporting these options properly will make users happy, and effectively provide two or more ports for the price of one.

5.12.1 Knobs WITH_* and WITHOUT_*

These variables are designed to be set by the system administrator. There are many that are standardized in the 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 a specific value 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 Ports that can be built both with and without X support are normally built with X support. If this variable is defined, then the version that does not have X support will be built instead. Knob Naming

Porters should use like-named knobs, both 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.

5.12.2 OPTIONS Background

The OPTIONS_* variables give the user installing the port a dialog showing the available options, and then saves those options to /var/db/ports/${UNIQUENAME}/options. The next time the port is built, the options are reused.

When the user runs make config (or runs make build for the first time), the framework checks for /var/db/ports/${UNIQUENAME}/options. If that file does not exist, the values of OPTIONS_* are used, and a dialog box is displayed where the options can be enabled or disabled. Then the options file is saved and the configured variables are 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.

make showconfig shows 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 described (optional, but strongly recommended):

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.

Tip: When describing options, view it from the perspective of the user: ``What does it do?'' and ``Why would I want to enable this?'' Do not just repeat the name. For example, describing the NLS option as ``include NLS support'' does not help the user, who can already see the option name but may not know what it means. Describing it as ``Native Language Support via gettext utilities'' is much more helpful.

OPTIONS can be grouped as radio choices, where only one choice from each group is allowed:


OPTIONS can be grouped as radio choices, where none or only one choice from each group is allowed:


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


OPTIONS can also be grouped as ``multiple-choice'' lists, where none or any option can 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. Check for Unset Port OPTIONS


Example 5-12. 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

CONFIGURE_ARGS+=	--without-examples

# Check other OPTIONS

.include <bsd.port.mk>

Example 5-13. 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. Do not use this method for new ports. Default Options

The following options are always on by default.

  • DOCS — build and install documentation.

  • NLS — Native Language Support.

  • EXAMPLES — build and install examples.

  • IPV6 — IPv6 protocol support.

Note: There is no need to add these to OPTIONS_DEFAULT. To have them show up in the options selection dialog, however, they must be added to OPTIONS_DEFINE.

5.12.3 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 5-14. Wrong Handling of an Option

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

In the example above, imagine a library libfoo is installed on the system. The 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 the 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 5-15. Correct Handling of an Option

LIB_DEPENDS+=		foo:${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.

Note: Under some circumstances, the shorthand conditional syntax can cause problems with complex constructs. If you receive errors such as Malformed conditional, an alternative syntax can be used.

# as an alternative to
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For questions about this documentation, e-mail <doc@FreeBSD.org>.