About Mac os 64-bit and 32-bit

I have Problem in 64-bit and 32-bit in mac. i am using mac10.6 version.it support 64-bit default. when i run my project in terminal using makefile ,how to run 32bit and 64 bit api's separately? why开发者_如何学编程 some Framework api available only in 32-bit(lower version)? please clear my doubt

Make sure you're using gcc version 4.0 or later, and add -arch flags for the architectures you want (e.g. -arch i386 or -arch x86_64 -arch ppc -arch ppc64 will compile for 32- and 63-bit Intel, and 32- and 64-bit PowerPC). Apple's 64-bit transition guide has a relevant section with details.

As for APIs: Apple has started to deprecate some APIs (mainly Carbon), and has not updated them to support 64-bit mode. Use Cocoa APIs instead. Again, Apple's 64-bit transition guide has a relevant section here, as well as a more detailed Carbon 64-bit guide.