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22  .TH funct "3rtapi" "2014-06-28" "LinuxCNC Documentation" "RTAPI"
23  .SH NAME
24  
25  rtapi_io.h \- RTAPI wrappers for linux kernel functionality
26  
27  .SH SYNTAX
28  .HP
29  #include <rtapi_io.h>
30  .HP
31  unsigned char rtapi_inb(unsigned short int port);
32  .HP
33  unsigned short rtapi_inw(unsigned short int port);
34  .HP
35  unsigned int rtapi_inl(unsigned short int port);
36  .HP
37  unsigned void rtapi_inb(unsigned char value, unsigned short int port);
38  .HP
39  unsigned void rtapi_inw(unsigned short value, unsigned short int port);
40  .HP
41  unsigned void rtapi_inl(unsigned int value, unsigned short int port);
42  
43  .SH DESCRIPTION
44  In kernel space, each rtapi_xxx or RTAPI_XXX identifier is mapped to the
45  underlying kernel functionality, if available.
46  
47  In userspace, or in kernels where the underlying functionality is not provided
48  by a kernel, generally another implementation--possibly with reduced
49  functionality--is provided.  (For example, the userspace implementation for
50  rtapi_device_register always succeeds)
51  .SH REALTIME CONSIDERATIONS
52  Call from init/cleanup code and from realtime tasks.  These functions will
53  cause illegal instruction exceptions in userspace components, as well as in
54  uspace rtapi_app when it is not setuid root.
55  .SH RETURN VALUE
56  As in Linux.
57  .SH SEE ALSO