How to define global shell functions in a Makefile?

Question

I want to define a shell function

#!/bin/sh

test ()
{
  do_some_complicated_tests $1 $2;
  if something; then
    build_thisway $1 $2;
  else
    build_otherway         


        

Answer 1

This solution does not rely on an external temporary file and does not force you to tinker with the SHELL variable.

TESTTOOL=sh -c '\
  do_some_complicated_tests $$1 $$2; \
  if something; then
    build_thisway $$1 $$2;
  else
    build_otherway $$1 $$2;
  fi' TESTTOOL

ifneq (,$(findstring n,$(MAKEFLAGS)))
TESTTOOL=: TESTTOOL
endif

foo: bar
    ${TESTTOOL} foo baz

The ifneq…endif block checks for the -n flag on the command line and sets the expansion of TESTTOOL to : TESTTOOL which is easy to read and safe to execute.

The best solution could be to turn the shell function into an actual program if this is an option for you.