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Key—type of data to retrieve. the main values fluctuate for every motive force and are outlined within the dossier config_keys. h less than the io subdirectory. buf—pointer to buffer the place info is put. len—pointer to dimension of information to retrieve. whilst the functionality returns, this parameter includes the particular measurement of information retrieved. Retrieve the run-time configuration for the machine laid out in the deal with parameter. the kind of info retrieved is laid out in the major parameter. Cyg_ErrNo cyg_io_set_config( cyg_io_handle_t deal with, cyg_uint32 key, const void *buf, cyg_uint32 *len ); handle—handle to the equipment. key—type of knowledge to set. the main values vary for every motive force and are outlined within the dossier config_keys. h lower than the io subdirectory. buf—pointer to info to configure the equipment. len—pointer to measurement of information to set. whilst the functionality returns, this parameter includes the particular dimension of knowledge retrieved. Set the run-time configuration for the gadget laid out in the deal with parameter. the kind of configuration info is laid out in the most important parameter. Code directory 7. four exhibits an instance utilizing the I/O Sub-System API. I/O regulate procedure a hundred forty five 1 #include 2 #include three #include four five // 6 // major place to begin for the appliance. 7 // eight void cyg_user_start( void ) nine { 10 cyg_io_handle_t tty_hdl; eleven int err; 12 char output_string[] = "Hello There!!! \n"; thirteen cyg_uint32 output_len = sizeof( output_string ); 14 15 err = cyg_io_lookup( "/dev/tty0", &tty_hdl ); sixteen 17 if ( err ) 18 { 19 diag_printf( "ERROR establishing machine tty0. \n" ); 20 go back; 21 } 22 23 err = cyg_io_write( tty_hdl, output_string, &output_len ); 24 25 if ( err ) 26 { 27 diag_printf( "ERROR writing to machine tty0. \n" ); 28 go back; 29 } 30 } Code directory 7. four I/O Sub-System API instance code. In Code directory 7. four we see an instance of writing a string to an I/O equipment. this instance assumes the "/dev/tty0" machine (CYGPKG_IO_SERIAL_TTY_TTY0) was once enabled, and configured correctly to be used with a serial port, less than the Serial gadget Drivers (CYGPKG_IO_SERIAL) package deal. We contain the I/O Sub-System API within the header dossier io. h as proven on-line 2. step one to exploit an I/O gadget is to acquire a deal with to the desired machine utilizing the cyg_io_lookup functionality, as proven on-line 15. This functionality is handed the identify of the equipment— to that end, "/dev/tty0"—which used to be configured within the CYGPKG_IO_SERIAL_TTY_TTY0 configuration choice. A deal with to the gadget is back upon profitable final touch of the functionality name and kept within the variable tty_hdl. sooner than continuing, we make sure that a sound equipment deal with was once again in our machine look up by means of checking the mistake code again as we see on-line sixteen. If an errors happened, we print out an mistakes message at the diagnostic port (line 19) and go back (line 20). 146 bankruptcy 7 • different eCos structure elements subsequent, we use the equipment deal with to write down out the message string within the variable output_string on-line 23. The functionality cyg_io_write outputs the variety of bytes handed within the 3rd parameter, output_len, utilizing the tty_hdl gadget.