USB Libraries Help > USB Host Libraries > USB CDC Host Library > Library Interface > b) Data Transfer Functions > USB_HOST_CDC_Write Function
MPLAB Harmony USB Stack
USB_HOST_CDC_Write Function

This function will write data to the attached CDC device. The function will write size amount of bytes. If the request was accepted, transferHandle will contain a valid transfer handle, else it will contain USB_HOST_CDC_TRANSFER_HANDLE_INVALID. The completion of the request will be indicated by the USB_HOST_CDC_EVENT_WRITE_COMPLETE event. The transfer handle will be returned in the event.

C
USB_HOST_CDC_RESULT USB_HOST_CDC_Write(
    USB_HOST_CDC_HANDLE handle, 
    USB_HOST_CDC_TRANSFER_HANDLE * transferHandle, 
    void * data, 
    size_t size
);
Preconditions

The client handle should be valid.

Parameters
Parameters 
Description 
handle 
handle to the CDC device instance to which the request should be sent.
 
transferHandle 
Pointer to USB_HOST_CDC_TRANSFER_HANDLE type of a variable. This will contain a valid transfer handle if the request was successful.
 
data 
pointer to the buffer containing the data to be written. The contents of the buffer should not be changed till the USB_HOST_CDC_EVENT_WRITE_COMPLETE event has occurred.
 
size 
Number of bytes to write. 
Returns

USB_HOST_CDC_RESULT_SUCCESS - The operation was successful. 

USB_HOST_CDC_RESULT_DEVICE_UNKNOWN - The device that this request was targeted to does not exist in the system. 

USB_HOST_CDC_RESULT_BUSY - The request could not be scheduled at this time. The client should try again. 

USB_HOST_CDC_RESULT_INVALID_PARAMETER - An input parameter was NULL. 

USB_HOST_CDC_RESULT_FAILURE - An unknown failure occurred. 

USB_HOST_CDC_RESULT_HANDLE_INVALID - The client handle is not valid.

Remarks

None.

Example