viWriteFromFile
Purpose
Take data from a file and write it out synchronously.
C Syntax
ViStatus viWriteFromFile(ViSession vi, ViString fileName, ViUInt32 count,
ViPUInt32 retCount)
Visual Basic Syntax
viWriteFromFile& (ByVal vi&, ByVal filename$, ByVal count&, retCount&)
Resource Classes
GPIB INSTR, GPIB INTFC, GPIB-VXI INSTR, Serial INSTR, TCPIP INSTR, TCPIP SOCKET, USB INSTR, USB RAW, VXI INSTR, VXI SERVANT
Parameters
| Name | Direction | Description |
|---|---|---|
|
vi |
IN |
Unique logical identifier to a session. |
|
fileName |
IN |
Name of file from which data will be read. |
|
count |
IN |
Number of bytes to be written. |
|
retCount |
OUT |
Number of bytes actually transferred. |
Return Values
| Completion Codes | Description |
|---|---|
|
VI_SUCCESS |
Transfer completed. |
| Error Codes | Description |
|---|---|
|
VI_ERROR_INV_OBJECT |
The given session reference is invalid. |
|
VI_ERROR_NSUP_OPER |
The given vi does not support this operation. |
|
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 expired before operation completed. |
|
VI_ERROR_RAW_WR_PROT_VIOL |
Violation of raw write protocol occurred during transfer. |
|
VI_ERROR_RAW_RD_PROT_VIOL |
Violation of raw read protocol occurred during transfer. |
|
VI_ERROR_INP_PROT_VIOL |
Device reported an input protocol error during transfer. |
|
VI_ERROR_BERR |
Bus error occurred during transfer. |
|
VI_ERROR_NCIC |
The interface associated with the given vi is not currently the controller in charge. |
|
VI_ERROR_NLISTENERS |
No-listeners condition is detected (both NRFD and NDAC are unasserted). |
|
VI_ERROR_IO |
An unknown I/O error occurred during transfer. |
|
VI_ERROR_FILE_ACCESS |
An error occurred while trying to open the specified file. Possible reasons include an invalid path or lack of access rights. |
|
VI_ERROR_FILE_IO |
An error occurred while accessing the specified file. |
|
VI_ERROR_CONN_LOST |
The I/O connection for the given session has been lost. |
Description
This write operation synchronously transfers data. The file specified in fileName is opened in binary read-only mode, and the data (up to end-of-file or the number of bytes specified in count) is read. The data is then written to the device. This operation returns only when the transfer terminates.
This operation is useful for sending data that was already processed and/or formatted.
Special Values for retCount Parameter
| Value | Action Description |
|---|---|
|
VI_NULL |
Do not return the number of bytes transferred. |
If you pass VI_NULL as the retCount parameter to the viWriteFromFile() operation, the number of bytes transferred will not be returned. This may be useful if it is important to know only whether the operation succeeded or failed.
Related Topics