CODEWITHSUNDEEP
cross-platformmakefilegnu-make
user457586
user457586

Reputation:

makefile custom functions

I'm trying to make a custom function in a Makefile to detect the current platform and return the proper file accordingly. Here is my attempt.

UNAME := $(shell uname -s)

define platform
    ifeq ($(UNAME),Linux)
        $1
    else ifneq ($(findstring MINGW32_NT, $(UNAME)),)
        $2
    else ifeq ($(UNAME),Darwin)
        $3
    endif
endef

all:
    @echo $(call platform,linux,windows,mac)

It fails with the following error.

/bin/sh: Syntax error: "(" unexpected
[Finished]make: *** [all] Error 2

What am I doing wrong?

Upvotes: 1

Views: 3409

Answers (2)

Maxim Egorushkin
Maxim Egorushkin

Reputation: 136266

Another option would be to concatenate outputs of uname to form a platform string in a certain format and have platform specific makefiles named accordingly:

ARCH := $(firstword $(shell uname -m))
SYS := $(firstword $(shell uname -s))

# ${SYS}.${ARCH} expands to Linux.x86_64, Linux.i686, SunOS.sun4u, etc..
include ${SYS}.${ARCH}.mk

Upvotes: 0

Eldar Abusalimov
Eldar Abusalimov

Reputation: 25493

ifeq ... else ... endif are conditional directives in GNU Make, they can't appear inside define ... endef because the latter treats them as a literal text. (Try to remove @ sign near echo command and you will see the actual result of evaluating platform function)

I'd move conditionals out of the define directive. Anyway, the target platform can't change during the execution of Make, so there is no need to parse $(UNAME) each time you call platform.

ifeq ($(UNAME),Linux)
    platform = $1
else ifneq ($(findstring MINGW32_NT, $(UNAME)),)
    platform = $2
else ifeq ($(UNAME),Darwin)
    platform = $3
endif

Upvotes: 3

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