GNU Make: Difference between revisions

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==.DELETE_ON_ERROR==
==Important [http://www.gnu.org/software/autoconf/manual/make/Special-Targets.html#Special-Targets Special Targets]==
===.DELETE_ON_ERROR===
* Generally, if make fails to build a target, and the target corresponds to a file, you want that file removed.
* Generally, if make fails to build a target, and the target corresponds to a file, you want that file removed.
** Why might this happen? Ctrl-c being pressed during a build. Multiple statements in a build recipe. Memory allocation failure during build. Any number of things.
** Why might this happen? Ctrl-c being pressed during a build. Multiple statements in a build recipe. Memory allocation failure during build. Any number of things.
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** <tt>kill -9</tt>'ing <tt>make</tt> will prevent this from happening! :/
** <tt>kill -9</tt>'ing <tt>make</tt> will prevent this from happening! :/
* [[gcc]] and some other tools will clean up on error, for some cases. Use <tt>.DELETE_ON_ERROR</tt> to be safe.
* [[gcc]] and some other tools will clean up on error, for some cases. Use <tt>.DELETE_ON_ERROR</tt> to be safe.
===.PHONY:===
* GNU Make manual section 4.6, "[http://www.gnu.org/software/autoconf/manual/make/Phony-Targets.html#Phony-Targets Phony Targets]"
* <tt>clean</tt>, <tt>all</tt>, <tt>test</tt> targets ought almost always be <tt>.PHONY</tt>
===.DEFAULT:===
* GNU Make manual section 10.6, "[http://www.gnu.org/software/autoconf/manual/make/Last-Resort.html Defining Last Resort Rules]"


==Make and [[subversion]]==
==Make and [[subversion]]==

Revision as of 10:07, 19 September 2009

Important Special Targets

.DELETE_ON_ERROR

  • Generally, if make fails to build a target, and the target corresponds to a file, you want that file removed.
    • Why might this happen? Ctrl-c being pressed during a build. Multiple statements in a build recipe. Memory allocation failure during build. Any number of things.
  • By adding .DELETE_ON_ERROR to the Makefile, this becomes the default behavior.
    • kill -9'ing make will prevent this from happening! :/
  • gcc and some other tools will clean up on error, for some cases. Use .DELETE_ON_ERROR to be safe.

.PHONY:

  • GNU Make manual section 4.6, "Phony Targets"
  • clean, all, test targets ought almost always be .PHONY

.DEFAULT:

Make and subversion

  • After running make in a pristine tree, the output of svn status ought be empty. Use svn:ignore properties to ignore your generated files.
    • Most importantly, svn status should not show any entries in the 'M'odified state. This indicates either generated files being checked into source control, or the build process modifying source in-place (the same thing, really)
    • If svn:ignore is properly used, the following rule suffices as a project-independent clean target, assuming the presence of xmlstarlet:
      svn --xml --no-ignore status | xmlstarlet sel -t -m //entry -i "wc-status[@item='ignored']" -v @path -n | xargs rm -rf