Page "FAQ" was changed by ryandesign@macports.org Diff URL: <https://trac.macports.org/wiki/FAQ?action=diff&version=142> Revision 142 Comment: minor edits to /usr/local section including adding a note to that trace mode doesn't work on El Capitan yet Changes: -------8<------8<------8<------8<------8<------8<------8<------8<-------- Index: FAQ ========================================================================= --- FAQ (version: 141) +++ FAQ (version: 142) @@ -75,20 +75,23 @@ === So with MacPorts under /opt/local I can use /usr/local freely? === #usrlocal -No, not entirely. Even with MacPorts living elsewhere, `/usr/local` can still interfere. +No. Even though MacPorts is installed elsewhere, software installed in `/usr/local` can still interfere with MacPorts. Some software (especially the GNU auto* tools and gcc) looks into `/usr/local` for external headers, libraries, and binaries. Certain ports might (and do) fail to build because during their build something incompatible is found and picked up from `/usr/local`. Good ports avoid this by explicitly specifying `--with-libfoo=/opt/local/lib/` or explicitly disabling all such possible dependencies altogether with `--disable-foo` or `--without-bar` but not all ports are able to do that. If you ask on a MacPorts mailing list about a port failing to build because it chokes on something -that it found and picked up in `/usr/local` you will probably be advised to temporarily rename -`/usr/local` to make it disappear entirely for the duration of the build. -Obviously, this wouldn't be possible to do if MacPorts itself lived under `/usr/local`. - -Note that starting with 2.3.0, MacPorts can automatically hide `/usr/local` (and all other files a port does not depend on) from ports' build systems. This feature is called trace mode and is activated by providing the `-t` flag to `port`, e.g. +that it found and picked up in `/usr/local` you will be asked to remove what you've installed in `/usr/local` +or to temporarily rename `/usr/local` to make it disappear entirely for the duration of the build. + +Note that starting with 2.3.0, MacPorts can automatically hide `/usr/local` (and all other files a port does not depend on) from ports' build systems. +This feature is called trace mode and is activated by providing the `-t` flag to `port`, e.g. {{{ sudo port -t install <portname> }}} You'll notice a small performance penalty when using trace mode, and a very small number of ports will fail to build due to the changes in the environment (currently, only the `go` and `sbcl` ports are known to be affected). Warnings about sandbox violations are normal when using trace mode. If a port fails to build in trace mode, the problem is very likely a bug. You should file a ticket if none exists yet. + +Note that trace mode in MacPorts 2.3.4 and earlier is not compatible with El Capitan. +A fix has been committed in r141420 but not yet released in a stable version of MacPorts. === How do I remove or uninstall MacPorts? === #uninstall -------8<------8<------8<------8<------8<------8<------8<------8<-------- -- Page URL: <https://trac.macports.org/wiki/FAQ> MacPorts <https://www.macports.org/> Ports system for OS X This is an automated message. Someone added your email address to be notified of changes on 'FAQ' page. If it was not you, please report to .