Question

I have a makefile template to compile a single DLL (for a plugin system). The makefile of the user looks like this:

EXTRA_SRCS=file1 file2 include makefile.in 

In the makefile.in I have:

plugin.dll: plugin.os $(patsubst %,%.os,$(EXTRA_SRCS)) 

Where plugin.os is the main C++ file to be compiled. Btw, the files ending is .os are the object files compiled for shared library (i.e. using the -fpic option with gcc)

Now, the problem is that the extra sources will probably (but not necessarily) be header files. Ideally I would like to add them as dependencies for the target plugin.os and the file.cpp, but only if they exist.

The method should work for both windows and linux, or at least be adaptable to each. However, I only use the GNU version of make.

Answer 1

Use the ‘wildcard’ function:

$(wildcard *.h) 

EDIT: in order to match a specific list, do

$(wildcard $(HEADER_FILES)) 

There is no need to use $(filter …), the wildcard function automatically filters files which don’t exist.