text: #ifndef _ASM_GENERIC_IOCTL_H
  #define _ASM_GENERIC_IOCTL_H
  
  #include <uapi/asm-generic/ioctl.h>
  
  /* provoke compile error for invalid uses of size argument */
  extern unsigned int __invalid_size_argument_for_IOC;
  #define _IOC_TYPECHECK(t) \
  	((sizeof(t) == sizeof(t[1]) && \
  	  sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
  	  sizeof(t) : __invalid_size_argument_for_IOC)
  #endif /* _ASM_GENERIC_IOCTL_H */
  