GNU make：如何确保模式只匹配没有目录的文件名

Question

I just want to copy files from other directories (before doing something). Because it's tedious to write the copy command for each file, I tried

%: ../src1/%
    @echo cp $^ .

%: ../src2/%
    @echo cp $^ .

all: file1 file2 file3 file4
    # do something

but this doesn't work because make tries to look into ../src2/../src2/../src2/../. . . . ../src2/../src2/../src2/../. . . . (I included echo for testing to prevent actual copying from happening. I keep forgetting what the "dry run" command line options is. . .)

I naïvely thought that there must be a way to force matches only to filenames that don't include directories.

Is there a way?

Answer 1

You can mark the "make anything" rules terminal with a double colon:

%:: ../src1/%
    @echo cp $^ .

%:: ../src2/%
    @echo cp $^ .

This does not answer your specific question of how to get Make to match only filenames without directories, but it does get Make to do what you want.

There is another approach that works and is closer to what you asked for: add pattern rules to satisfy Make:

../src1/%:
    @: # do nothing

%: ../src1/%
    @echo cp $^ .

EDIT: Or better still, us one dummy pattern rule to cover all source directories:

../%:
        @: # do nothing