@brief Re-read the line info. @param line GPIO line object. @return 0 if the operation succeeds. In case of an error this routine returns -1 and sets the last error number.
The line info is initially retrieved from the kernel by gpiod_chip_get_line() and is later re-read after every successful request. Users can use this function to manually re-read the line info when needed.
We currently have no mechanism provided by the kernel for keeping the line info synchronized and for the sake of speed and simplicity of this low-level library we don't want to re-read the line info automatically everytime a property is retrieved. Any daemon using this library must track the state of lines on its own and call this routine if needed.
The state of requested lines is kept synchronized (or rather cannot be changed by external agents while the ownership of the line is taken) so there's no need to call this function in that case.