[ILUG] Linking question

[hmoreau at digiserve.ie]

On  7 Nov, Mel wrote:

> They are two static libs that are part of an SDK for music
> encoding/decoding. At some stage both of them have similar functions such
> as frame counters and global constants. I can strip out some of the
> functions but not all of them. I was hoping there was some way you could
> tell the linker thant when there is duplicate symbols, just take them from
> the first library
> 
> not looking like it though.
> 

/* If you have a c file like this (one.c):- */

char *something;

int afunction (int v)
{
    something = malloc(v);
}

/* and another c file (two.c) :- */

int something;

int bfunction ()
{
   something = 10;
}

These two files are compiled into separate libraries.  How could the
linker make up its mind as to which declaration of something is the one
to use?  If your libraries contain extern/global data with the same
name(s) then they can't be used together. Even if the names and types
were the same (as in C++ with name mangling), and linking was possible,
there would be a strong likelihood that strange things would happen.
-- 
--harry