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Manual page for ARCH(3)

NXGetAllArchInfos, NXGetLocalArchInfo, NXGetArchInfoFromName, NXGetArchInfoFromCpuType, NXFindBestFatArch, NXCombineCpuSubtypes - get architecture information

SYNOPSIS

#include <mach-o/arch.h>
extern const NXArchInfo *NXGetAllArchInfos(void);
extern const NXArchInfo *NXGetLocalArchInfo(void);
extern const NXArchInfo *NXGetArchInfoFromName(const char *name);
extern const NXArchInfo *NXGetArchInfoFromCpuType(cpu_type_t cputype, cpu_subtype_t cpusubtype);
extern struct fat_arch *NXFindBestFatArch(cpu_type_t cputype, cpu_subtype_t cpusubtype, struct fat_arch *fat_archs, unsigned long nfat_archs);
extern cpu_subtype_t NXCombineCpuSubtypes(cpu_type_t cputype, cpu_subtype_t cpusubtype1, cpu_subtype_t cpusubtype2);

DESCRIPTION

These functions are intended for use in programs that have to deal with fat files or programs that can target multiple architectures. Typically, a program will use a command-line argument that starts with -arch name, where this specifies an architecture. These functions and data structures provide some help for processing architecture flags and then processing the contents of a fat file.

The structure NXArchInfo is defined in <mach-o/arch.h> as follows:

	typedef struct {
		const char *name;
		cpu_type_t cputype;
		cpu_subtype_t cpusubtype;
		enum NXByteOrder byteorder;
		const char *description;
	} NXArchInfo;

It is used to hold the name of the architecture and the corresponding CPU type and CPU subtype, together with the architecture's byte order and a brief description string.

The currently known architectures are:

Name CPU Type CPU Subtype Description
hppa CPU_TYPE_HPPA CPU_SUBTYPE_HPPA_ALL HP-PA
i386 CPU_TYPE_I386 CPU_SUBTYPE_I386_ALL Intel 80x86
i860 CPU_TYPE_I860 CPU_SUBTYPE_I860_ALL Intel 860
m68k CPU_TYPE_MC680x0 CPU_SUBTYPE_MC680x0_ALL Motorola 68K
m88k CPU_TYPE_MC88000 CPU_SUBTYPE_MC88000_ALL Motorola 88K
m98k CPU_TYPE_MC98000 CPU_SUBTYPE_MC98000_ALL Power PC
mips CPU_TYPE_MIPS CPU_SUBTYPE_MIPS_ALL MIPS
sparc CPU_TYPE_SPARC CPU_SUBTYPE_SUN4_ALL SPARC
vax CPU_TYPE_VAX CPU_SUBTYPE_VAX_ALL DEC VAX

i486 CPU_TYPE_I386 CPU_SUBTYPE_486 Intel 486
i486SX CPU_TYPE_I386 CPU_SUBTYPE_486SX Intel 486SX
i586 CPU_TYPE_I386 CPU_SUBTYPE_586 Intel 586
i586SX CPU_TYPE_I386 CPU_SUBTYPE_586SX Intel 586SX
m68030 CPU_TYPE_MC680x0 CPU_SUBTYPE_MC68030_ONLY Motorola 68030
m68040 CPU_TYPE_MC680x0 CPU_SUBTYPE_MC68040 Motorola 68040

The first set of entries are used for the architecture family. The second set of entries are used for a specific architecture, when more than one specific architecture is supported in a family of architectures.

NXGetAllArchInfos() returns a pointer to an array of all known NXArchInfo structures. The last NXArchInfo is marked by a NULL name.

NXGetLocalArchInfo() returns the NXArchInfo for the local host, or NULL if none is known.

NXGetArchInfoFromName() and NXGetArchInfoFromCpuType() return the NXArchInfo from the architecture's name or CPU type/CPU subtype combination. A CPU subtype of CPU_SUBTYPE_MULTIPLE can be used to request the most general NXArchInfo known for the given CPU type. NULL is returned if no matching NXArchInfo can be found.

NXFindBestFatArch() is passed a CPU type and CPU subtype and a set of fat_arch structs. It selects the best one that matches (if any), and returns a pointer to that fat_arch struct (or NULL). The fat_arch structs must be in the host byte order and correct such that fat_archs really points to enough memory for nfat_arch structs. It is possible that this routine could fail if new CPU types or CPU subtypes are added and an old version of this routine is used. But if there is an exact match between the CPU type and CPU subtype and one of the fat_arch structs, this routine will always succeed.

NXCombineCpuSubtypes() returns the resulting CPU subtype when combining two different CPU subtypes for the specified CPU type. If the two CPU subtypes can't be combined (the specific subtypes are mutually exclusive), -1 is returned, indicating it is an error to combine them. This can also fail and return -1 if new CPU types or CPU subtypes are added and an old version of this routine is used. But if the CPU subtypes are the same, they can always be combined and this routine will return the CPU subtype passed in.