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C Type Sizes

Table shows byte sizes of the corresponding bytes, with alignment in parentheses (if different).

Architecture		char	short	int	long	long long	pointer	bool	float	double	long double
Darwin 32-bit Power PC	OS X	1	2	4	4	8	4	1	4	8	16[2]
Darwin 64-bit Power PC	OS X	1	2	4	8	8	8	1	4	8	16
Darwin IA-32	OS X	1	2	4	4	8(4)	4	1	4	8(4)	16
System V i386	Linux	1	2	4	4	n/a	4	n/a	4	8(4)	12(4)
System V AMD64	Linux x86-64 OS X x86_64	1	2	4	8	8	8	1	4	8	16
Windows x86 (32-bit)		1		4	4	8	4
Windows x64		1	2	4	4		8		4	8	n/a
ARM 32-bit		1	2	4	4	8	4	1	4	8	8
ARM 64-bit	AArch64; LP64	1	2	4	8	8	8	1	4	8	16
MacOS 68k		1	2	4(2)	4(2)		4(2)		4	8/10/12^[1](2)	8
MacOS PowerPC		1					4		4	8

[1]64-bit type is IEEE 754 binary64, 80-bit type is Apple SANE Extended, 96-bit type is Motorola 68881

[2]8 bytes prior to OS X v10.4

OS X ABI Function Call Guide

System V Application Binary Interface— Intel386 Architecture Processor Supplement

System V Application Binary Interface— AMD64 Architecture Processor Supplement

Procedure Call Standard for the ARM® Architecture

CodeWarrior® Targeting the MacOS

MacOS Runtime Architectures

architecture	scratch	preserved	parameters	return	frame	stack	globals
MacOS 68k	A0-A1,D0-D2,F0-F3	A2-A4,D3-D7,F4-F7			A6	A7	A5
MacOS PowerPC	GPR0
Win32 STDCALL	EAX, ECX, EDX	EBX, ESI, EDI, everything else	stack, right-to-left, callee deallocates	RAX	EBP	ESP
Microsoft x64	RAX, RCX, RDX, R8-R11	RBX, RBP, RDI, RSI, RSP, R12-R15 XMM6-XMM15	RCX, RDX, R8-R9 XMM0-XMM3 stack, right-to-left, caller-saved	RAX; XMM0	RBP	RSP
System V AMD64			RDI, RSI, RDX, RCX, R8-R9 XMM0-XMM7	RAX, RAX+RDX	RBP	RSP	R10 ('static chain')