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Calling Conventions

The x86 C-language calling convention (application binary interface, or ABI) specifies that arguments to functions are passed on the stack. The PowerPC ABI specifies that arguments to functions are passed in registers. Also, x86 has far fewer registers, so many local variables use the stack for their storage. Thus, programming errors, or other operations that access past the end of a local variable array or otherwise incorrectly manipulate values on the stack may be more likely to crash applications on x86 systems than on PowerPC.

For detailed information about the IA-32 ABI, see Mac OS X ABI Function Call Guide. This document describes the function-calling conventions used in all the architectures supported by Mac OS X. See also “32-Bit Application Binary Interface.”

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