Rockwell Automation 1747-PCINT API Software for 1746 I/O - Manual (Page 63)

OC_DemandInputScan Library of Routines 6–9
Publication 1747-6.5.3 June 1998
OC_DemandInputScan OC_DemandInputScan forces the scanner to immediately perform an input scan.
Syntax:
int OC_DemandInputScan(HANDLE handle, int mode);
Parameters:
Description:
If an I/O scan is in progress when this function is called, the input scan is performed after the current scan
has completed.
The scanner updates the input image with data read from the modules. Use OC_ReadInputImage to read
data from the input image.
Return Value:
Considerations:
Supported in the DOS API library and the Windows NT API library
Example:
HANDLE Handle;
int retcode;
retcode = OC_DemandInputScan( Handle, OCWAIT );
Parameter: Description:
handle Must be a valid handle returned from OC_OpenScanner
mode
If mode is:
OCWAIT OC_DemandInputScan waits for the input scan to be
completed before returning to the caller.
OCNOWAITOC_DemandInputScan returns immediately.
Name: Value: Description:
SUCCESS 0 demand input request was successful
ERR_OCACCESS 2
handle does not have access to scanner
ERR_OCRESPONSE
10
scanner did not respond to request
ERR_OCSCANCFG 14 scanner has not been configured