Makefile that distinguishes between Windows and Unix-like systems

Question

I would like to have the same Makefile for building on Linux and on Windows. I use the default GNU make on Linux and the mingw32-make (also GNU make) on Windows.

I want the Makefile to detect whether it operates on Windows or Linux.

For example make clean command on Windows looks like:

clean:
    del $(DESTDIR_TARGET)

But on Linux:

clean:
    rm $(DESTDIR_TARGET)

Also I would like to use different directory separator on Windows (\) and Linux (/).

It is possible to detect Windows operating system in Makefile?

PS: I do not want to emulate Linux on Windows (cygwin etc.)

There is similiar question: OS detecting makefile, but I didn't find the answer here.

Windows is able to handle both slashes "/" and "\" are equivalent. — Ency, Oct 30 '10 at 13:17
If this is for a substantial project, I wonder if it'd be worth letting autotools handle some of the portability stuff? — Cascabel, Oct 30 '10 at 14:30
@Jefromi: autotools assumes a basic UNIX toolset (sh, m4, sed, rm, ...). @tomp: Might as well install them on windows (from MSYS or GnuWin) and spend your efforts on the more challenging portability issues. — ephemient, Oct 30 '10 at 16:07
@ephemient: Ah, right, my bad. I'm not really a windows person. (But now I'm confused - can't the mingw toolchain provide that too? I know, the OP said no linux emulation.) — Cascabel, Oct 30 '10 at 16:57
@Ency, the "del" command on Windows doesn't like to be given a "/". — Imbue, Jan 20 '11 at 00:28

Paul Hutchinson · Accepted Answer · 2018-10-22T17:05:26.513

63

I solved this by looking for an env variable that will only be set on windows.

ifdef OS
   RM = del /Q
   FixPath = $(subst /,\,$1)
else
   ifeq ($(shell uname), Linux)
      RM = rm -f
      FixPath = $1
   endif
endif

clean:
    $(RM) $(call FixPath,objs/*)

Because %OS% is the type of windows, it should be set on all Windows computers but not on Linux.

The blocks then setups up variables for the different programs as well as a function for converting the forward slashes into backslashes.

You to have to use $(call FixPath,path) when you call an outside command (internal commands work fine). You could also use something like:

/ := /

and then

objs$(/)*

if you like that format better.

edited Oct 22 '18 at 17:05

answered Dec 22 '10 at 16:15

Paul Hutchinson

1,578
15
21

2

Thanks for this. I switch between MinGW on Windows and GCC on Linux, this works great. – Imbue Jan 20 '11 at 00:27
1

In mingw it should be `SYSTEMROOT` in uppercase – SystemParadox Jan 26 '13 at 20:51
1

You can also check for ComSpec, that is only defined on Windows – kebs Apr 04 '13 at 06:47
If you're running COMMAND.COM for some reason, you should also be checking for SYSTEMROOT in uppercase: "SystemRoot" won't be defined with that capitalisation (whereas it will in CMD.EXE). – Jan 19 '16 at 04:24
Updated example to use the upper case version of SYSTEMROOT – Paul Hutchinson May 06 '16 at 18:29
System root is sensitive in mingw32-make and it doesn't work after either. – Tomáš Zato Feb 14 '17 at 13:29
There is already $(RM) in make environments, already depending on OS. – Sandburg Mar 01 '19 at 13:09
In GnuWin32's `make` the predefined variable `$(RM)` expands to `rm -f` in CMD.EXE – veganaiZe Jun 08 '21 at 19:21

score 49 · Answer 2 · answered Jun 16 '11 at 12:19

49

The SystemRoot trick didn't work for me on Windows XP but this did:

ifeq ($(OS),Windows_NT)
    #Windows stuff
    ...
else
    #Linux stuff
    ....
endif

answered Jun 16 '11 at 12:19

tomsgd

1,080
1
11
24

this might be tricky if you have cygwin installed and make executable comes from cygwin. You will get OS=Windows_NT but you can use Linux commands like mkdir -p. The direction of the directory separator is also important – sagi Mar 30 '20 at 20:54

score 10 · Answer 3 · answered Oct 30 '10 at 13:23

10

You should probably use the $(RM) variable to remove some files.

answered Oct 30 '10 at 13:23

Antoine Pelisse

12,871
4
34
34

score 1 · Answer 4 · answered Aug 25 '18 at 10:58

Checking WINDIR or COMSPEC is case-sensitive. Instead, I came up with the following solution, hope that helps someone someday:

# detect if running under unix by finding 'rm' in $PATH :
ifeq ($(wildcard $(addsuffix /rm,$(subst :, ,$(PATH)))),)
WINMODE=1
else
WINMODE=0
endif

ifeq ($(WINMODE),1)
# native windows setup :
UNLINK = del $(subst /,\,$(1))
CAT = type $(subst /,\,$(1))
else
# cross-compile setup :
UNLINK = $(RM) $(1)
CAT = cat $(1)
endif

score 0 · Answer 5 · answered Oct 30 '10 at 15:36

0

I would like to have the same Makefile for building on Linux and on Windows.

Maybe you will like CMake

answered Oct 30 '10 at 15:36

Please put the explanation how to use tool – Vlad Jun 15 '22 at 20:57

Makefile that distinguishes between Windows and Unix-like systems

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