imgCreateBuffer
Usage
rval imgCreateBuffer(SESSION_ID sid, uInt32 where, uInt32 bufferSize, void** bufPtrAddr);
Purpose
Creates a frame buffer based on the region of interest (ROI) in the associated session. Passing NULL or zero for the SESSION_ID is valid. In this case, you must pass a buffer size. If bufferSize is zero, the buffer size is computed as follows:
[ROI height] x [rowPixels] x [number of bytes per pixel]
The function returns an error if the buffer size is smaller than the minimum buffer size required for the session.
Parameters
| Name | Type | Direction |
| sid | SESSION_ID | input |
| where | uInt32 | input |
| bufferSize | uInt32 | input |
| bufPtrAddr | void** | output |
| rval | Int32 | output |
Parameter Discussion
sid: valid SESSION_ID
where: value that indicates if the buffer should be stored in system memory or in onboard memory on the image acquisition device, as specified by the following constants:
| IMG_HOST_FRAME | Specifies the new buffer is created in the host computer memory. |
| IMG_DEVICE_FRAME | Specifies the new buffer is created in onboard memory. This feature is not available on the NI PCI/PXI-1407, NI PCIe-1427, NI PCIe-1429, and NI PCIe-1430 devices. |
bufferSize: size of the buffer you want to create, in bytes.
bufPtrAddr: pointer to an area of memory that stores the new buffer address.
 |
Note If you use IMG_DEVICE_FRAME, do not access the returned value of bufPtrAddr. |
Return Value
This function returns 0 on success. On failure, this function returns an error code. For information about the error code, call imgShowError.