/** 'hal_link()' links a pin to a signal. 'pin_name' and 'sig_name'
are strings containing the pin and signal names. If the pin is
already linked to a signal, the original connection is unchanged.
If the original signal is the same as the desired one, the command
returns success, otherwise it returns failure. (Use 'hal_unlink'
if you need to change an existing connection.) If the signal
already has other pins linked to it, they are unaffected - one
signal can be linked to many pins, but a pin can be linked to only
one signal.
On success, hal_link() returns HAL_SUCCESS, on failure it returns a
negative error code.
*/
extern int hal_link(char *pin_name, char *sig_name);
/** 'hal_unlink()' unlinks any signal that is connected to a pin.
'pin_name' is a string containing the pin name. If the pin is
not linked to any signal, the hal_unlink() returns succcess.
On success, hal_unlink() returns HAL_SUCCESS, on failure it
returns a negative error code.
*/
extern int hal_unlink(char *pin_name);