FreeBSD/Linux Kernel Cross Reference
sys/include/minix/ioctl.h

     /*      minix/ioctl.h - Ioctl helper definitions.       Author: Kees J. Bot
      *                                                              23 Nov 2002
      *
      * This file is included by every header file that defines ioctl codes.
      */
     
     #ifndef _M_IOCTL_H
     #define _M_IOCTL_H
     
    #ifndef _TYPES_H
    #include <sys/types.h>
    #endif
    
    #if _EM_WSIZE >= 4
    /* Ioctls have the command encoded in the low-order word, and the size
     * of the parameter in the high-order word. The 3 high bits of the high-
     * order word are used to encode the in/out/void status of the parameter.
     */
    #define _IOCPARM_MASK   0x1FFF
    #define _IOC_VOID       0x20000000
    #define _IOCTYPE_MASK   0xFFFF
    #define _IOC_IN         0x40000000
    #define _IOC_OUT        0x80000000
    #define _IOC_INOUT      (_IOC_IN | _IOC_OUT)
    
    #define _IO(x,y)        ((x << 8) | y | _IOC_VOID)
    #define _IOR(x,y,t)     ((x << 8) | y | ((sizeof(t) & _IOCPARM_MASK) << 16) |\
                                    _IOC_OUT)
    #define _IOW(x,y,t)     ((x << 8) | y | ((sizeof(t) & _IOCPARM_MASK) << 16) |\
                                    _IOC_IN)
    #define _IORW(x,y,t)    ((x << 8) | y | ((sizeof(t) & _IOCPARM_MASK) << 16) |\
                                    _IOC_INOUT)
    #else
    /* No fancy encoding on a 16-bit machine. */
    
    #define _IO(x,y)        ((x << 8) | y)
    #define _IOR(x,y,t)     _IO(x,y)
    #define _IOW(x,y,t)     _IO(x,y)
    #define _IORW(x,y,t)    _IO(x,y)
    #endif
    
    int ioctl(int _fd, int _request, void *_data);
    
    #endif /* _M_IOCTL_H */

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