viSetBuf
Syntax
viSetBuf(ViSession vi, ViUInt16 mask, ViUInt32 size);
Description
Set the size for the formatted I/O and/or serial communication buffer(s). This operation changes the buffer size of the read and/or write buffer for formatted I/O and/or serial communication. The mask parameter specifies which buffer to set the size of. The mask parameter can specify multiple buffers by bit-ORing any of the following values together.
|
Flag |
Interpretation |
|
VI_READ_BUF |
Formatted I/O read buffer. |
|
VI_WRITE_BUF |
Formatted I/O write buffer. |
|
VI_IO_IN_BUF |
I/O communication receive buffer. |
|
VI_IO_OUT_BUF |
I/O communication transmit buffer. |
For backward compatibility, VI_IO_IN_BUF is the same as VI_ASRL_IN_BUF and VI_IO_OUT_BUF is the same as VI_ASRL_OUT_BUF. Since not all serial drivers support user-defined buffer sizes, it is possible that a specific implementation of VISA may not be able to control this feature. If an application requires a specific buffer size for performance reasons, but a specific implementation of VISA cannot guarantee that size, it is recommended to use some form of handshaking to prevent overflow conditions.
Parameters
|
Name |
Dir |
Type |
Description |
|
vi |
IN |
ViSession |
Unique logical identifier to a session. |
|
mask |
IN |
ViUInt16 |
Specifies the type of buffer. |
|
size |
IN |
ViUInt32 |
The size to be set for the specified buffer(s). |
Return Values
|
Type ViStatus |
This is the function return status. It returns either a completion code or an error code as follows. |
|
Completion Codes |
Description |
|
VI_SUCCESS |
Buffer size set successfully. |
|
VI_WARN_NSUP_BUF |
The specified buffer is not supported. |
|
Error Codes |
Description |
|
VI_ERROR_ALLOC |
The system could not allocate the buffer(s) of the specified size because of insufficient system resources. |
|
VI_ERROR_INV_MASK |
The system cannot set the buffer for the given mask. |
|
VI_ERROR_INV_SESSION |
The given session or object reference is invalid (both are the same value). |
|
VI_ERROR_RSRC_LOCKED |
Specified operation could not be performed because the resource identified by vi has been locked for this kind of access. |
See Also