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- Describe how to assign run dependencies to build dependencies correctly

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Submitted by:	danfe
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Gabor Pali 2010-08-04 17:58:06 +00:00
parent 7b68a5ef5a
commit 0f71b08a02
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=36168
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en_US.ISO8859-1/books/porters-handbook/book.sgml
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@ -3181,11 +3181,15 @@ ALWAYS_KEEP_DISTFILES= yes
<sect1 id="makefile-depend">
<title>Dependencies</title>
<para>Many ports depend on other ports. There are seven variables that
you can use to ensure that all the required bits will be on the
user's machine. There are also some pre-supported dependency
variables for common cases, plus a few more to control the behavior
of dependencies.</para>
<para>Many ports depend on other ports. This is very convenient
and nice feature of most Unix-like operating systems,
including &os;. It allows not having to bundle common
dependencies with every port or package, since a lot of ports
would share them. There are seven variables that can be used
to ensure that all the required bits will be on the user's
machine. There are also some pre-supported dependency
variables for common cases, plus a few more to control the
behavior of dependencies.</para>
<sect2>
<title><makevar>LIB_DEPENDS</makevar></title>
@ -3278,6 +3282,36 @@ ALWAYS_KEEP_DISTFILES= yes
not on the user's system. The <replaceable>target</replaceable>
part can be omitted if it is the same as
<makevar>DEPENDS_TARGET</makevar>.</para>
<para>Quite common situation is when
<makevar>RUN_DEPENDS</makevar> is literally the same as
<makevar>BUILD_DEPENDS</makevar>, especially if ported
software is written in a scripted language or if it requires
the same run-time environment used to build it. In this
case, it is very tempting, and indeed natural to directly
assign one to another:</para>
<programlisting>RUN_DEPENDS= ${BUILD_DEPENDS}</programlisting>
<para>However, doing so can and often will result in
run-time dependencies be polluted by superfluous entries, not
present in original port's <makevar>BUILD_DEPENDS</makevar>.
It happens due to the fact that &man.make.1 is being lazy
when it evaluates assignments like these. Most probably
additional dependencies will be pulled by
<filename>ports/Mk/bsd.*.mk</filename> when processing
<makevar>USE_<replaceable>*</replaceable></makevar>
variables, which most ports contain. For example, such
direct assignment along with
<literal>USE_GMAKE=yes</literal> will bring
<application>gmake</application> into
<makevar>RUN_DEPENDS</makevar>, despite that it was not
included explicitly in <makevar>BUILD_DEPENDS</makevar>. To
prevent this from happening, immediate expansion assignment
should be used, i.e. expand the value before assigning it
to the variable:</para>
<programlisting>RUN_DEPENDS:= ${BUILD_DEPENDS}</programlisting>
</sect2>
<sect2>