How to get pattern rules to match file names with spaces in Makefile?

Question

In the GNU make docs, '%' is documented to match "any nonempty substring". However, it seems it actually only matches non-empty substrings that do not contain whitespace. For example, say you do this:

mkdir /tmp/foo
cd /tmp/foo
echo 'int main() { return 0; }' > "test.c"
echo 'int main() { return 0; }' > "test space.c"

Now, you should be able to build these using GNU Make's built-in pattern rules:

anthony@Zia:/tmp/foo$ make "test"
cc     test.c   -o test
anthony@Zia:/tmp/foo$ make "test space"
make: *** No rule to make target `test space'.  Stop.

The same problem happens when you write a makefile.

anthony@Zia:/tmp/foo$ rm test
anthony@Zia:/tmp/foo$ echo 'all: test test\ space' > Makefile 
anthony@Zia:/tmp/foo$ make
cc     test.c   -o test
make: *** No rule to make target `test space', needed by `all'.  Stop.

Even if you explicitly add in a %: %.c rule, the result is the same. But if you add in an explicit rule to the Makefile, like this, it works:

test\ space: test\ space.c
    $(CC) -o "$@" "$<"     # first char is tab, of course.

Is there a trick to get spaces to work with implicit rules?

edit

I've sent a bug report: http://lists.gnu.org/archive/html/bug-make/2011-06/msg00002.html

Antananarivo

Answer 1

I don't believe so. The notion of a list of whitespace-separated tokens being passed around as a string is pretty deeply ingrained in make. Those lists are parsed and reparsed. There's a reason why spaces in directory and file names is considered bad practice in the UNIX world.

Milliemillieme

Well, I'm not sure spaces in filenames are really considered bad practice in the Linux world anymore, except for some limited things like source code files… unfortunately, this stuff came from a vendor. I guess I could file a bug report. Or look for a make alternative. – Antananarivo

I sent a bug report: lists.gnu.org/archive/html/bug-make/2011-06/msg00002.html – Antananarivo

Spaces are still considered bad practice in filenames in the Linux world. The only place it is acceptable is user-created filenames. With shell tools, you will (quite simply) suffer if you use spaces. – Unfeigned

It's not a bad practice, but rather a must because of limitations of tools like make, or poorly written shell scripts. – Juror

Answer 2

This is a kludge, but as of today, people still get given paths with spaces in sometimes.

Anyway, making a link instead of directly accessing the directory in the % rule works OK.

# GNU makefile
DIR_WITH_SPACE=/c/Users/me/My\ Code

# *** DOESN'T WORK ***
%.h : $(DIR_WITH_SPACE)/%.h
    cp -v "$<" "$@"

fix:
  ln -s $(DIR_WITH_SPACES) dir_fixed

# Does work :)
%.h : dir_fixed/%.h
    cp -v "$<" "$@"

Anamorphosis