Re: Return type of dlsym

["Clive D.W. Feather" <yyyyy@xxxxxxxxx>]

Wojtek Lerch said:
> Splitting dlsym() into two functions would be a more elegant way, but it
> might break some existing code more seriously.  Personally, I think that
> doing both is the best solution.

It's just struck me that the split has another benefit: if the symbol is in
the library, but not with the type expected by the programmer, having
separate functions allows the problem to be diagnosed. In other words, we
have:

                           data pointer         function pointer
    void * dlsym ()        returns pointer      returns NULL or a cookie [*]
    void * dlsym_d ()      returns pointer      returns NULL
    fptr_t dlsym_f ()      returns NULL         returns pointer

[*] On some implementations, casting this cookie to fptr_t will produce the
same value that dlsym_f would have done. On other implementations it will
produce a value of no use whatsoever.

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