A Divendres 25 Novembre 2005 13:55, Goswin von Brederlow va escriure: > Leopold Palomo-Avellaneda <[EMAIL PROTECTED]> writes: > > Hi, > > > > I have a question that maybe could be an off topic but I think that it > > could be interesting for the amd64 users. > > > > I have a library code with some executables of a device. This device uses > > the parallel port and provides a library to use it with some more > > functionalities (provides some .so and some .h to link with). > > > > Of course I don't have the source code and worst the library is compiled > > for RedHat 7.2 :-( (gcc-2.96 ...) > > > > I have though that maybe it could be possible to develop a wrapper to use > > the library in the way that I can update compiler and distro and also > > arch amd64) but really, I don't know if is this possible and how to > > begin. > > > > Is this possible or I'm asking something stupid? > > It is possible. Nothing is impossible. But it is also quite stupid. > > You would need a very god reason, like you get paid for it, to do this. > > > If it's possible, how I can do that? rewriting the headers and a cpp code > > calling the library functions? and the compiler, have I to make some > > special flag? can I reuse a .so as a .a? > > > > This idea could help to the people that have devices that have libraries > > to develop with them but not the source code and for example want to > > change of distro or upgrade an a amd64. Of course that if the library is > > compiled in a 32 bits it will be 32 bit, but it's possible to mix 64bit > > and 32bits code? > > You need a library that mmaps the old library into a 32bit address > space, provides a wraper function for every function that uses 64bit > calling convention, translates those into 32bit variables, copies all > pointer targets into the 32bit address space and adjusts them, calls > the origianl function with the gcc-2.96 C calling conventions (which > differ miniscule from current gcc) and in 32bit mode, and reverses all > that with the results. Especialy for the pointer conversions you need > detailed knowledge of every function, so no automatic conversion > possible there. > > On the other hand you might just be able to just use the library as is > in 32bit mode, unless some glibc symbols clash or they use one of the > very rare construct with abi changes. And thats why the wraper is stupid.
I forgot to mention that it's not c but that it's c++ with ABI from the redhat 7.2 (gcc-2.96) . :-( If it's possible to use swig to generate wrapper and then use the generated wrapper on another machine. Regards, Leo -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
