SCardIsValidContext function (winscard.h)
The SCardIsValidContext function determines whether a smart card context handle is valid.
Syntax
LONG SCardIsValidContext(
[in] SCARDCONTEXT hContext
);
Parameters
[in] hContext
Handle that identifies the resource manager context. The resource manager context can be set by a previous call to SCardEstablishContext.
Return value
This function returns one of the following values.
Return code | Description |
---|---|
|
The hContext parameter is valid. |
|
The hContext parameter is not valid. |
|
An error code. For more information, see Smart Card Return Values. |
Remarks
Call this function to determine whether a smart card context handle is still valid. After a smart card context handle has been set by SCardEstablishContext, it may become not valid if the resource manager service has been shut down.
Examples
The following example shows determining whether a smart card context handle is valid.
// Check the smart card context handle.
// hContext was set previously by SCardEstablishContext.
LONG lReturn;
lReturn = SCardIsValidContext(hContext);
if ( SCARD_S_SUCCESS != lReturn )
{
// Function failed; check return value.
if ( ERROR_INVALID_HANDLE == lReturn )
printf("Handle is invalid\n");
else
{
// Some unexpected error occurred; report and bail out.
printf("Failed SCardIsValidContext - %x\n", lReturn);
exit(1); // Or other appropriate error action.
}
}
else
{
// Handle is valid; proceed as needed.
// ...
}
Requirements
Requirement | Value |
---|---|
Minimum supported client | Windows XP [desktop apps only] |
Minimum supported server | Windows Server 2003 [desktop apps only] |
Target Platform | Windows |
Header | winscard.h |
Library | Winscard.lib |
DLL | Winscard.dll |