To: djgpp AT delorie DOT com
Subject: Re: Dynamic loading of functions
Message-ID: <19970214.172521.7647.0.chambersb@juno.com>
References: <Pine DOT VUL DOT 3 DOT 91 DOT 970214094133 DOT 8488I-100000 AT zeus DOT adv-boeblingen DOT de>
From: chambersb AT juno DOT com (Benjamin D Chambers)
Date: Fri, 14 Feb 1997 20:23:29 EST


On Fri, 14 Feb 1997 09:51:08 -0600 Lennart Steinke
<steinke AT zeus DOT adv-boeblingen DOT de> writes:
>Hi!
>
>I'm currently playing with the idea of loading function dynamically
>(for plug ins). It's working, but I've some questions:
>
>1) Do I have to lock the memory of the funtion after loading or
>   not?
Don't know.

>2) Are there already libs for djgpp which allow dynamic binding?
Yes.  They're called DLM's, you can do EVERYTHING in them that you can do
in a normal object file.  They're actually better, because you can
overload function names in vanilla C (no C++), by unloading one set of
commands and loading a different set.

...Chambers

>
>Here's the simple and short demo source:
>
>====Start
>#include <stdio.h>
>#include <stdlib.h>
>
>static void __begin_func(void){};
>
>int f1(int a)
>{
>    printf("\nTest %i\n",a);
>    return a*2;
>}
>
>static void __end_func(void){};
>
>int (*f2)(int a);
>
>void main(void)
>{
>    void *p_func;
>    FILE *f;
>    long int size;
>    int a=2;
>
>    p_func= &__begin_func+ sizeof(int);
>    size = (long int) (&__end_func- &__begin_func);
>
>    f=fopen("test.fnc","wb");
>    fwrite(p_func, size, 1, f);
>    fclose(f);
>
>    f=fopen("test.fnc","rb");
>    (void *)f2 = malloc(size);
>    fread(f2,size,1, f);
>    fclose(f);
>
>    a=f2(a);
>    printf("%i\n",a);
>
>}
>
>====End
>
>
>Lenny
>-- 
>Lennart Steinke (steinke AT adv-boeblingen DOT de)
>http://mars.adv-boeblingen.de/~steinke
>
>
>