Vhl_Is_Selected - Siemens SIMATIC RF1000 Operating Instructions Manual

Programming
7.2 Programming via USB/RS232 interface (using DLL functions)
Table 7-13
Parameter
vhl_get_snr
Return value
7.2.1.12

vhl_is_selected

This function checks whether the card selected the last time the "vhl_select" function was
executed is still or once again located in the antenna field. If the card is there, the status "OK" is
returned.
Note that this function always returns the return value "CARD_NOT_SELECTED_ERR" when a
card is displayed to the reader without the "vhl_select" function being executed first.
Function call
int
vhl_is_selected(
int Handle,
int * Status
);
Table 7-14
Parameter
vhl_is_selected
Return value
46
Description of the parameters
Description
This function call returns the serial number of the currently selected card.
Handle The session key returned by the "brp_open_usb_session" or "brp_open_seri‐
al_session" function.
Snr Serial number of the card (LSB first)
Length Length of the serial number in bytes
Status
• OK
• CARD_NOT_SELECTED_ERR
You can find more detailed information on the reader status in the section
"Status codes (Page 66)".
• BRP_OK
• CARD_NOT_SELECTED_ERR
You will find more information on return values in the section "Return values
(Page 52)".
Description of the parameters
Description
This function call checks if the card selected during the last execution of the
"vhl_select" function is still in the antenna field or if it has returned to the
antenna field.
Handle The session key returned by the "brp_open_usb_session" or "brp_open_seri‐
al_session" function.
Status
• OK
• CARD_NOT_SELECTED_ERR
You can find more detailed information on the reader status in the section
"Status codes (Page 66)".
• BRP_OK
You will find more information on return values in the section "Return values
(Page 52)".
Operating Instructions, 05/2023, C79000-G8976-C432-10
SIMATIC RF1000