From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Fri, 19 Nov 2010 08:55:18 +0100 Subject: [Buildroot] [PATCH] autotools: add with/without and enable/disable helpers In-Reply-To: <1290141237-30539-1-git-send-email-vapier@gentoo.org> References: <1290141237-30539-1-git-send-email-vapier@gentoo.org> Message-ID: <20101119085518.655d8c0d@surf> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hello, On Thu, 18 Nov 2010 23:33:57 -0500 Mike Frysinger wrote: > Rather than have to write ugly logic in every package .mk file to check > a config var and then expand into a --{en,dis}able-foo flag, add helpers > so code can cleanly expand things. Sounds a very good idea! > +# $(call _USE_CONF,enable,disable,LIB_FFMPEG,video,blah) -> --enable-video=blah if LIB_FFMPEG > +# $(call _USE_CONF,with,without,LIB_FFMPEG,video) -> --with-video if LIB_FFMPEG > +_USE_CONF = $(shell \ > + opt="$(5)"; test "$${opt:+set}" = "set" && opt="=$${opt}"; \ > + test "$(BR2_$(3))" = "y" \ > + && echo "--$(1)-$(4)$${opt}" \ > + || echo "--$(2)-$(4)") However, I'm worried that this will start a shell process when evaluating *each* USE_ENABLE/USE_WITH call, and this will slow down the start up of Buildroot. In the past, we were forking/execing "tr" once per-package and it was slowing down Buildroot startup needlessly (~10-15 seconds doing hundreds of fork/exec). It'd be nicer if we could use a pure Makefile implementation. What about a simpler : USE_WITH = $(if $(BR2_$(1)),--with-$(2),--without-$(2)) USE_ENABLE = $(if $(BR2_$(1),--enable-$(2),--disable-$(2))) However, their usage might be a little limited: often when the option is enabled, we need to add a dependency to the package as well. Regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com