[30735] trunk/doc-new/man/xml/portfile-phase.7.xml

[markd at macports.org]

"Daniel J. Luke" <dluke at geeklair.net> writes:
>The -j is actually a make option.
>
>The make manpage describes it like this:
>       -j [jobs], --jobs[=jobs]
>             Specifies the number of jobs (commands) to run  
>simultaneously.  If
>             there  is  more than one -j option, the last one is  
>effective.  If
>             the -j option is given without an argument, make  will   
>not  limit
>             the number of jobs that can run simultaneously.
>
>I believe the idea is that the user can specify the number of  
>simultaneous jobs they want, and if a port has this flag it will pass  
>the appropriate -j N (where N is the number of jobs) to make. At some  
>point, macports will probably be updated to detect a good default  
>value for N (that the user could override), but I don't believe that  
>there's code for that yet.


Weissmann Markus <mww at macports.org> writes:
>I've just added a way to automatically set the number of build jobs  
>(if desired):
>If the number of build jobs is set to "0" (in the config file), the  
>number of jobs is set to the number of cores.
>
>This works only on Mac OS X (and FreeBSD -- though untested).


I pasted the raw text from my latest doc update on "use_parallel_build".
Is this accurate?


use_parallel_build

This keyword is for specifying whether or not it is safe for a port to use
multiple cpus or multiple cores in parallel during its build phase. This
keyword passes the -j [jobs] option to make, where jobs is obtained from
the variable buildmakejobs in macports.conf. This variable may also be set
to 0 so the number of jobs is set to the number of cores detected during
the build phase.

Mark