NAME

       rtapi_io.h - RTAPI wrappers for linux kernel functionality

SYNTAX

       #include <rtapi_io.h>

       unsigned char rtapi_inb(unsigned short int port);

       unsigned short rtapi_inw(unsigned short int port);

       unsigned int rtapi_inl(unsigned short int port);

       unsigned void rtapi_outb(unsigned char value, unsigned short int port);

       unsigned void rtapi_outw(unsigned short value, unsigned short int port);

       unsigned void rtapi_inl(unsigned int value, unsigned short int port);

       int rtapi_ioperm(unsigned long from, unsigned long num, int turn_on);

       unsigned void rtapi_outl(unsigned int value, unsigned short int port);

DESCRIPTION

       In kernel space, each rtapi_xxx or RTAPI_XXX identifier is mapped to the underlying kernel functionality,
       if available.

       In  userspace,  or  in  kernels where the underlying functionality is not provided by a kernel, generally
       another implementation--possibly with reduced functionality--is provided.  (For  example,  the  userspace
       implementation  for  rtapi_device_register  and  the  kernel  space implementation of rtapi_ioperm always
       succeeds)

REALTIME CONSIDERATIONS

       Call from init/cleanup code and from realtime tasks.  These  functions  will  cause  illegal  instruction
       exceptions in non-realtime components, as well as in uspace rtapi_app when it is not setuid root.

RETURN VALUE

       As in Linux.

SEE ALSO

       inb(3), inw(3), inl(3), outb(3), outw(3), outl(3), ioperm(3),

AUTHOR

       Jeff Epler

LinuxCNC Documentation                             2022-11-29                                      funct(3rtapi)