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
     universal files or programs that can target multiple architectures.  Typ-
     ically, 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 universal file.

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

                   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
     ppc           CPU_TYPE_POWERPC    CPU_SUBTYPE_POWERPC_ALL     PowerPC
     ppc64         CPU_TYPE_POWERPC64  CPU_SUBTYPE_POWERPC64_ALL   PowerPC
                                                                   64-bit
     i386          CPU_TYPE_I386       CPU_SUBTYPE_I386_ALL        Intel 80x86
     x86_64        CPU_TYPE_X86_64     CPU_SUBTYPE_X86_64_ALL      Intel
     ppc7400       CPU_TYPE_POWERPC    CPU_SUBTYPE_POWERPC_7400    PowerPC
                                                                   7400
     ppc7450       CPU_TYPE_POWERPC    CPU_SUBTYPE_POWERPC_7450    PowerPC
                                                                   7450
     ppc970        CPU_TYPE_POWERPC    CPU_SUBTYPE_POWERPC_970     PowerPC 970
     i486          CPU_TYPE_I386       CPU_SUBTYPE_486             Intel 486
     i486SX        CPU_TYPE_I386       CPU_SUBTYPE_486SX           Intel 486SX
     pentium       CPU_TYPE_I386       CPU_SUBTYPE_PENT            Intel
                                                                   Pentium
     i586          CPU_TYPE_I386       CPU_SUBTYPE_586             Intel 586
     pentpro       CPU_TYPE_I386       CPU_SUBTYPE_PENTPRO         Intel
                                                                   Pentium Pro
     i686          CPU_TYPE_I386       CPU_SUBTYPE_PENTPRO         Intel
                                                                   Pentium Pro
     pentIIm3      CPU_TYPE_I386       CPU_SUBTYPE_PENTII_M3       Intel
                                                                   Pentium II
                                                                   Model 3
     pentIIm5      CPU_TYPE_I386       CPU_SUBTYPE_PENTII_M5       Intel
                                                                   Pentium II
                                                                   Model 5
     pentium4      CPU_TYPE_I386       CPU_SUBTYPE_PENTIUM_4       Intel
                                                                   Pentium 4
     m68030        CPU_TYPE_MC680x0    CPU_SUBTYPE_MC68030_ONLY    Motorola
                                                                   68030
     m68040        CPU_TYPE_MC680x0    CPU_SUBTYPE_MC68040         Motorola
                                                                   68040
     hppa7100LC    CPU_TYPE_HPPA       CPU_SUBTYPE_HPPA_7100LC     HP-PA
                                                                   7100LC

     The first set of entries are used for the architecture family.  The sec-
     ond 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 NXArch-
     Info 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 gen-
     eral 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_archs 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

                                 July 28, 2005