Re: universal binaries

[Markus Hitter]

Am 13.01.2007 um 19:04 schrieb Rogelio Serrano:

> How does apple do it?

Universal binaries are two or more ordinary binaries in a row,  
together with a header in front of it. All this is put into one file.

To launch a Universal Binary (UB), the kernel's execve() recognizes  
the UB header in addition to ordinary binaries (and scripts). If  
execve() finds such a header, it sets a file offset to the binary  
matching the current architecture and starts over.

> With Mach-o?

I don't think this is limited to some sort of ABI other than by  
patent issues. In principle, you should even be able to stitch  
together mach-o and ELF binaries. You'd have to modify the current  
Mac OS X kernel to get this working.

> is it enough to compile and cross
> compile and just put them all together in an application bundle?

No.

The stitching tool is named "lipo", to help your googling.


HTH,
Markus

- - - - - - - - - - - - - - - - - - -
Dipl. Ing. Markus Hitter
http://www.jump-ing.de/