Question about build dependencies

[Ryan Schmidt]

Well, it doesn't depend on the user's PATH. MacPorts internally sets  
the PATH to a very specific value which includes the OS directories  
and the MacPorts prefix. And it searches those paths only.

Also, this is not specific to the depends_build section. Any  
dependency (build, library or runtime) can be written in this way.


On May 28, 2008, at 23:53, Tabitha McNerney wrote:

> Ah, thanks, that makes sense -- in other words, if there is a build  
> depends that can already be satisfied by a build that the operating  
> system (e.g., Mac OS X) provides, then it will go ahead and use  
> that without complaining if, at the same time, a MacPorts-supplied  
> build is not available (e.g., it all depends on if the binary is in  
> the PATH).
>
> Thanks Ryan for help in understanding this!
>
> Best,
>
> T.M.
>
> On Wed, May 28, 2008 at 6:43 PM, Ryan Schmidt  
> <ryandesign at macports.org> wrote:
> On May 28, 2008, at 22:38, Tabitha McNerney wrote:
>
> I have what might seem to be a dumb question. I noticed today that  
> the MacPort named "libiconv" version 1.12 has a build dependency on  
> another port named gperf, specifically:
>
> $ port deps libiconv
> libiconv has build dependencies on:
>        gperf
>
> What I find very interesting about this situation, however, is that  
> on my MacPorts system I have not consciously built / installed the  
> gperf port. But I have successfully built and installed the  
> libiconv port. Therefore, I am wondering, how is it possible that  
> the libiconv port was able to build and install without the gperf  
> port dependency having first been built?
>
> Apparently libiconv requires gperf. I don't know anything about  
> this; that's the way the port was when I inherited it.
>
> The dependency is declared like this:
>
> depends_build \
>        bin:gperf:gperf
>
> That means if a binary (the "bin" part) called "gperf" (the first  
> "gperf" part) does not exist on the computer, then install the  
> gperf port (the 2nd "gperf" part).
>
> On my Tiger system, a gperf binary is provided by Mac OS X in /usr/ 
> bin/gperf so the gperf port does not need to be installed.
>
> Usually ports depend on other ports only. In this case, the  
> previous maintainer of libiconv must've thought the gperf provided  
> by Mac OS X was sufficient. I don't even know what gperf does.
>
>