WaitForRxMessagesWithTimeOut Method - intrepidcs API
C/C++ declare - VB declare - VB.NET delcare - C# declare - Parameters - Return Values - Remarks - C/C++ example - VB example - VB.NET example - C# example

This method is used to wait a specified amount of time for received messages from the neoVI hardware.

C/C++ Declare

int _stdcall icsneoWaitForRxMessagesWithTimeOut(int hObject, unsigned int iTimeOut);

Visual Basic Declare

Public Declare Function icsneoWaitForRxMessagesWithTimeOut Lib "icsneo40.dll" (ByVal hObject As Long, ByVal iTimeOut As Long) As Long


Visual Basic .NET Declare

Public Declare Function icsneoWaitForRxMessagesWithTimeOut Lib "icsneo40.dll" (ByVal hObject As Int32, ByVal iTimeOut As UInt32) As Int32


C# Declare

[DllImport("icsneo40.dll")]
public static extern Int32 icsneoWaitForRxMessagesWithTimeOut(Int32 hObject, UInt32 iTimeOut);


Parameters

hObject
    [in] Specifies the driver object created by OpenNeoDevice.

iTimeOut
    [in] Specifies the amount of time in milliseconds that the function will wait for a received message before returning.

Return Values

0 if no message was received during the wait period. 1 if a message was received. -1 will be returned if there is an error condition. GetLastAPIError must be called to obtain the specific error. The errors that can be generated by this function are:

NEOVI_ERROR_DLL_NEOVI_NO_RESPONSE = 75

Remarks

This function allows an application to avoid 'polling' for received messages. It will return as soon as a message is received or when the timeout specified has been reached. 

Examples

Visual Basic Example

Private m_hObject As Long '// Declared at form level and previously open with a call to OpenNeoDevice

Dim lResult As Long
Dim iTimeOut As Long
iTimeOut = 5000 '//Set timeout to 5 seconds

lblWaitForRxMessageWithTimeOutResult.Caption = "Status"
DoEvents()

'//This function will block until, A: A Message is received by the hardware, or B: the timeout is reached
lResult = icsneoWaitForRxMessagesWithTimeOut(m_hObject, iTimeOut)
If lResult = 1 Then
    'Message received before timeout
    lblWaitForRxMessageWithTimeOutResult.Caption = "Message received"
    '//Do something with the messages received
    Call cmdReceive_Click()
Else
    'Timeout reached and no messages received
    lblWaitForRxMessageWithTimeOutResult.Caption = "Message Not received"
    '//Take action if no messages were received
End If
 

C/C++ Example

int hObject = 0; // holds a handle to the neoVI object
icsSpyMessage stMessages[19999]; // holds the received messages
int iResult;
int iNumberOfErrors;
int iNumberOfMessages;
unsigned int iTimeOut = 5; //milliseconds
bool bDone = false;

while(!bDone)
{
    iResult = icsneoWaitForRxMessagesWithTimeOut(hObject, iTimeOut);
    
    if(iResult == 0)
        continue; //no messages received

    iResult = icsneoGetMessages(hObject,stMessages,&iNumberOfMessages,&iNumberOfErrors);

    if(iResult == 0)
        MessageBox(hWnd,TEXT("Problem Reading Messages"),TEXT("neoVI Example"),0);
    else
        MessageBox(hWnd, TEXT("Messages Read Successfully"),TEXT("neoVI Example"),0);
}

return 0;

Visual Basic .NET Example

Private m_hObject As Integer '// Declared at form level and previously open with a call to OpenNeoDevice

Dim iResult As Integer
Dim iTimeOut As UInt32

iTimeOut = Convert.ToUInt32(5000)

lblWaitForRxMessageWithTimeOutResult.Text = "Status"
Application.DoEvents()

'//This function will block until, A: A Message is received by the hardware, or B: the timeout is reached
iResult = icsneoWaitForRxMessagesWithTimeOut(m_hObject, iTimeOut)
If iResult = 1 Then
    'Message received before timeout
    lblWaitForRxMessageWithTimeOutResult.Text = "Message received"
    Call cmdReceive_Click(sender, e)
    '//Do something with the messages received
Else
    'Timeout reached and no messages received
    lblWaitForRxMessageWithTimeOutResult.Text = "Message Not received"
    '//Take action if no messages were received
End If

C# Example

//Declared at form level and previously open with a call to OpenNeoDevice
int m_hObject; //handle for device

int iResult;
UInt32 iTimeOut = 5000; //Set timeout to 5 seconds

lblWaitForRxMessageWithTimeOutResult.Text = "Status";
Application.DoEvents();

//This function will block until, A: A Message is received by the hardware, or B: the timeout is reached
iResult = icsNeoDll.icsneoWaitForRxMessagesWithTimeOut(m_hObject, iTimeOut);
if (iResult == 1)
{
    //Message received before timeout
    lblWaitForRxMessageWithTimeOutResult.Text = "Message received";
    //Do something with the messages received
    cmdReceive_Click(sender, e);
}
else
{
    //Timeout reached and no messages received
    lblWaitForRxMessageWithTimeOutResult.Text = "Message Not received";
    //Take action if no messages were received
}
 

Last Updated : Tuesday, December 16, 2008