In message: <[EMAIL PROTECTED]> Peter Pentchev <[EMAIL PROTECTED]> writes: : On Sat, Apr 13, 2002 at 12:48:59AM -0600, M. Warner Losh wrote: : > In message: <[EMAIL PROTECTED]> : > Peter Pentchev <[EMAIL PROTECTED]> writes: : > : On Fri, Apr 12, 2002 at 10:09:16PM -0600, M. Warner Losh wrote: : > : > In message: <[EMAIL PROTECTED]> : > : > Dmitry Mottl <[EMAIL PROTECTED]> writes: : > : > : How can I link C program with different versions of the same library? : > : > : > : > You can't. : > : : > : Okay; what exactly is it that you cannot do - link a program against : > : two versions of the same library simultaneously (I thought so), or : > : link a program against a *specified* version of a library (what, I think, : > : the original poster clarifies he wants to do, for no specific reason)? : > : > You can't, generally, link against two different versions of the same : > library. The reason is that you get mutiply defined symbols because : > it is very very very rare that two different versions of the same : > library wouldn't have any symbols that overlap. : : Well, actually, your 'full path' suggestion gave me an idea.. : : [roam@straylight:p6 ~/c/misc/foo]$ cc -o foo18 foo18.c /usr/lib/libncurses.so.5 :/usr/lib/compat/libncurses.so.3 : [roam@straylight:p6 ~/c/misc/foo]$ ldd ./foo18 : ./foo18: : libncurses.so.5 => /usr/lib/libncurses.so.5 (0x28065000) : libncurses.so.3 => /usr/lib/compat/libncurses.so.3 (0x280a7000) : libc.so.4 => /usr/lib/libc.so.4 (0x280b8000) : libmytinfo.so.2 => /usr/lib/compat/libmytinfo.so.2 (0x28151000) : [roam@straylight:p6 ~/c/misc/foo]$ : : Duplicate symbols are not a problem - AFAIK, symbols are resolved : in the order the libraries were specified on the linker command line, : and, consequently, in the order the dependencies are recorded into : the resulting executable file. So, if foo18 calls an ncurses.5 routine, : it will be invoked from ncurses.5; if foo18 calls a routine that is : not present in ncurses.5, it will be invoked from ncurses.3. : : So it is actually possible; not that I have ANY idea what the point : would be..
Ah, this just hides the problem of incompatible interfaces :-(. that's why the libraries have different version numbers: they have a different API. Warner To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
