GNU make with many target directories

Question

I have to integrate the generation of many HTML files in an existing Makefile. The problem is that the HTML files need to reside in many different directories. My i

Answer 1

The best solution I found so far is to generate an implicit rule per target directory via foreach-eval-call, as explained in the GNU make manual. I have no idea how this scales to a few thousand target directories, but we will see...

If you have a better solution, please post it!

Here is the code:

rootdir  = /home/user/project/doc
HPC      = /usr/local/bin/hpc

html = $(rootdir)/build/doc/2009/06/01/some.html \
       $(rootdir)/build/doc/2009/06/02/some.html

targetdirs = $(rootdir)/build/doc/2009/06/01 \
             $(rootdir)/build/doc/2009/06/02

define generateHtml
 $(1)/%.html: %.st
    -mkdir -p $(1)
    $(HPC) -o $$@ $$<
endef   

$(foreach targetdir, $(targetdirs), $(eval $(call generateHtml, $(targetdir))))

.PHONY: all
all: $(html)