viQueryf
Purpose
Performs a formatted write and read through a single call to an operation.
C Syntax
ViStatus viQueryf(ViSession vi, ViString writeFmt, ViString readFmt,...)
Visual Basic Syntax
N/A
Resource Classes
GPIB INSTR, GPIB-VXI INSTR, Serial INSTR, TCPIP INSTR, TCPIP SOCKET, VXI INSTR
Parameters
| Name | Direction | Description |
|---|---|---|
|
vi |
IN |
Unique logical identifier to a session. |
|
writeFmt |
IN |
String describing the format of write arguments. |
|
readFmt |
IN |
String describing the format of read arguments. |
|
... |
IN/OUT |
Parameters to which write and read format strings are applied. |
Return Values
| Completion Codes | Description |
|---|---|
|
VI_SUCCESS |
Successfully completed the query operation. |
| Error Codes | Description |
|---|---|
|
VI_ERROR_INV_OBJECT |
The given session reference is invalid. |
|
VI_ERROR_IO |
Could not perform Read/Write operation because of I/O error. |
|
VI_ERROR_RSRC_LOCKED |
Specified operation could not be performed because the resource identified by vi has been locked for this kind of access. |
|
VI_ERROR_TMO |
Timeout occurred before Read/Write operation completed. |
|
VI_ERROR_INV_FMT |
A format specifier in the writeFmt or readFmt string is invalid. |
|
VI_ERROR_NSUP_FMT |
The format specifier is not supported for current argument type. |
|
VI_ERROR_ALLOC |
The system could not allocate a formatted I/O buffer because of insufficient resources. |
Description
This operation provides a mechanism of Send, then receive typical to a command sequence from a commander device. In this manner, the response generated from the command can be read immediately.
This operation is a combination of the viPrintf() and viScanf() operations. The first n arguments corresponding to the first format string are formatted by using the writeFmt string, then sent to the device. The write buffer is flushed immediately after the write portion of the operation completes. After these actions, the response data is read from the device into the remaining parameters (starting from parameter n + 1) using the readFmt string.
 |
Note Because the prototype for this function cannot provide complete type-checking, remember that all output parameters must be passed by reference. |
Related Topics