Simulate package visibility of functions of different modules contained in a single directory.

build.sh

	#!/bin/bash

	# BUILD library which contains all modules of the package
	echo"Build package.o from module1.c and module2.c"
	gcc -c -o module1.o module1.c
	gcc -c -o module2.o module2.c
	ld -o package.o -r module1.o module2.o
	symbols=(`nm package.o`)
	for((i=0;i<${#symbols[*]};i=i+1))do
	if [ "${symbols[$i]}"!="T" ];thencontinue;fi
	function_name=${symbols[$((i+1))]}
	if [ "${function_name#private}"="$function_name" ];thencontinue;fi
	echo"Change function '$function_name' to package scope (private)"
	objcopy -L "$function_name" package.o
	done

	echo"Generate main.c and link it with package.o"
	echo"main() calls public_function from module1.c in package.o"
	echo"#include <stdio.h>"> main.c
	echo"#include \"module1.h\"">> main.c
	echo>> main.c
	echo"int main(int argc, const char* argv[])">> main.c
	echo"{">> main.c
	echo" public_function();">> main.c
	echo" return 0;">> main.c
	echo"}">> main.c

	gcc -o main main.c package.o
	echo"::Start main::"
	./main
	echo"::End main::"

	echo
	echo"Generate main.c and link it with package.o"
	echo"main() now tries to call private_function from module2.c in package.o"
	echo"This will generate a compiler error !"
	gcc -o main "-Dpublic_function=private_function" main.c package.o

	#include<stdio.h>
	#include"module1.h"// header of this module
	#include"module2.h"// contains private_function

	voidpublic_function()
	{
	printf("enter public_function()\n");
	private_function();
	printf("exit public_function()\n");
	}

	#ifndefPACKAGE_MODULE1_HEADER
	#definePACKAGE_MODULE1_HEADER

	voidpublic_function(void);

	#endif

	#include<stdio.h>
	#include"module2.h"// header of this module

	voidprivate_function()
	{
	printf("enter private_function()\n");
	printf("exit private_function()\n");
	}

	#ifndefPACKAGE_MODULE2_HEADER
	#definePACKAGE_MODULE2_HEADER

	voidprivate_function(void);

	#endif