ICCPLATFORMSIGNATURE

typedef enum
{
    NoPlatformSignature = 0x00000000L, /* No Platform Signature */
    MacintoshSignature = 0x4150504CL, /* 'APPL' */
    MicrosoftSignature = 0x4D534654L, /* 'MSFT' */
    SolarisSignature = 0x53554E57L, /* 'SUNW' */
    SGISignature = 0x53474920L  /* 'SGI ' */
} ICCPLATFORMSIGNATURE;

This enumerated type is used within the ICC_HEADER structure to indicate the primary platform.