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How to make another function entry point other than main () in C

Each program has main()

, and the execution of the program begins with it. Is it possible to write a program without main()

and make another function an entry point? If so, can someone please tell me how this can be done? Am I using Linux?

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2 answers


If you are compiling with gcc, specifying the option -e <symbol>

will allow you to change the entry point to a function symbol()

.



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There is a solution for building an executable shared library where you can build a program using another function as an entry point.

The code looks like this:

#include <stdio.h>
#include <stdlib.h>
const char __invoke_dynamic_linker[] __attribute__ ((section (".interp"))) 
    = "/lib/ld-linux.so.2";
void fun()
{
    printf("This is fun./n");
    exit(0);
}


Then build your program as a shared library and specify func as the entry point:

$ gcc -fpic -shared -o fun.so -Wl,-e,fun fun.c
$ ./fun.so

The problem with this method is that func cannot have normal arguments like we have in the main function, this is because we don't have a c library to initialize the main arguments.

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