Scanlab RTC 5 PC Interface Board Installation And Operation Manual page 403

Ctrl Command select_rtc
Function defines, in a multi-board system, the active RTC
program). See
Call
NoOfSelectedCard = select_rtc( CardNo )
Parameter
CardNo
Result The returned (unsigned 32-bit) value is
• CardNo if access rights exist for the specified board or if the specified board is not allo-
cated to another application (in this latter case, access rights are acquired through
select_rtc – as via acquire_rtc, see below)
• the number of the active board if CardNo exceeds the number of RTC
during initialization or if CardNo = 0
• 0 otherwise (particularly when the specified board is reserved by another application or
if a version compatibility error is detected and activation of the board therefore can't
succeed)
RTC5_VERSION_MISMATCH )
Comments • Activation of a board for an application already occurs when the DLL for this application
is initialized (see
bility of changing the active board at any time. All the application's commands subse-
quent to select_rtc (except for multi-board commands) will be forwarded to the
corresponding active board.
• If the specified board is reserved for another application, select_rtc will have no effect
(return value 0,
• If no access rights are assigned for the specified board, and it is not in use by another
application, then the board will not only be activated but also – if it passed the version
compatibility check (see below) – automatically reserved for this application (as via
acquire_rtc) and therefore unavailable to other applications (return value: CardNo). If a
board is acquired (as via acquire_rtc), a version compatibility check will be performed.
If a version error is detected, then access to the board will be denied and select_rtc will
have no effect (return code 0,
RTC5_ACCESS_DENIED|RTC5_VERSION_MISMATCH).
• If the specified board is already the active board for this application, select_rtc will have
no effect (return value: CardNo).
• The select_rtc command also has no effect if CardNo exceeds the number of RTC
boards found during initialization (see
(real boards begin at 1). The return value is then the number of the active board (see
above). Therefore, the command select_rtc( 0 ) can be used to determine the
number of the active board at any time.
• The select_rtc command is also available without explicit access rights to a particular
®
RTC 5 board.
• select_rtc is not available as a multi-board command.
® ®
RTC 4 RTC 5 With the RTC
With the RTC
in some circumstances (as via acquire_rtc) for the specified board when none had existed
or it has no effect.
®
RTC 5 PC Interface Board
Rev. 1.9 e
10 Commands And Functions
chapter 6.6, page 83.
(DLL-internal) number of the RTC
(get_last_error return code RTC5_ACCESS_DENIED and possibly
init_rtc5_dll, page
get_last_error return code RTC5_ACCESS_DENIED).
get_last_error
®
4, this command only activates the specified board (unconditionally).
®
5, this command additionally returns a value and either assigns access rights
®
5 board for an application (user
®
5 board as an unsigned 32-bit value
306). The select_rtc command offers the possi-
return code
rtc5_count_cards, page
®
5 boards found
®
5
396) or if CardNo = 0
403