CODEWITHSUNDEEP
c++cmakefilegnu-make
martega
martega

Reputation: 2143

GNU Make: How to add an option in front of every entry of a list

I have a problem where I want to create a variable that looks like this,

INCDIRS = -I dir0 -I dir1 -Idir2 -I dir3 ... -I dirN

where dir1, ... , dirN are the names of all the subdirectories some base directory, base_dir.

How would I go about building up this variable? Originally, I thought I could do the following,

INCDIRS = $(shell for x in `find base_dir -type -d -print`; do echo -I $x; done;)

but this just results in

INCDIRS = -I -I -I -I ... -I

If anyone could explain how to do this, or explain why my original command got the output that it did, I would greatly appreciate it. Thanks!

Upvotes: 1

Views: 129

Answers (2)

Idelic
Idelic

Reputation: 15582

You could first get the list of directories, then add -I in front of each one:

SOURCE_DIRS := $(shell find base_dir -type d -print)
INCDIRS      = $(addprefix -I,$(SOURCE_DIRS))

which may be better if you need $(SOURCE_DIRS) for something else.

Upvotes: 2

David Hammen
David Hammen

Reputation: 33126

You have two errors in your INCDIRS assignment. One is in the find command. It should be find -type d -print (or just find -type d; the -print is superfluous here). The other error the use of $x. You need to escape the $ with another $:

INCDIRS = $(shell for x in `find base_dir -type d -print`; do echo -I $$x; done;)

Upvotes: 2

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