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

TL;DR:

In your makefile:

SHELL=bash
BASH_FUNC_command%%=() { ... }
export BASH_FUNC_command%%

Long answer

I've done something similar with bash in a non-make context which works here.

I declared my shell functions in bash and then exported them with:

export -f function-name

They are then naturally available if the same shell is invoked as a sub-process, in your case, from make.

Example:

$ # define the function
$ something() { echo do something here ; }
$ export -f something

$ # the Makefile
$ cat > Makefile <<END
SHELL=bash
all: ; something
END
$

Try it out

$ make
something
do something here
$

How does this look in the environment?

$ env | grep something
BASH_FUNC_something%%=() { echo do something here

So the question for you would be how to set the environment variables from within the Makefile. The pattern seems to be BASH_FUNC_function-name%%=() { function-body }

Directly within make

So how does this work for you? Try this makefile

SHELL=bash
define BASH_FUNC_something-else%%
() {
  echo something else
}
endef
export BASH_FUNC_something-else%%

all: ; something-else

and try it:

$ make
something-else
something else

It's a bit ugly in the Makefile but presents no ugliness for make -n