viReadToFile
Purpose
Read data synchronously, and store the transferred data in a file.
C Syntax
ViStatus viReadToFile(ViSession vi, ViString fileName, ViUInt32 count, ViPUInt32 retCount)
Visual Basic Syntax
viReadToFile& (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 to which data will be written. |
|
count |
IN |
Number of bytes to be read. |
|
retCount |
OUT |
Number of bytes actually transferred. |
Return Values
| Completion Codes | Description |
|---|---|
|
VI_SUCCESS |
The operation completed successfully and the END indicator was received (for interfaces that have END indicators). |
|
VI_SUCCESS_TERM_CHAR |
The specified termination character was read. |
|
VI_SUCCESS_MAX_CNT |
The number of bytes read is equal to count. |
| Error Codes | Description |
|---|---|
|
VI_ERROR_INV_OBJECT |
The given session or object reference is invalid (both are the same value). |
|
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_OUTP_PROT_VIOL |
Device reported an output protocol error during transfer. |
|
VI_ERROR_BERR |
Bus error occurred during transfer. |
|
VI_ERROR_INV_SETUP |
Unable to start read operation because setup is invalid (due to attributes being set to an inconsistent state). |
|
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 deasserted). |
|
VI_ERROR_ASRL_PARITY |
A parity error occurred during transfer. |
|
VI_ERROR_ASRL_FRAMING |
A framing error occurred during transfer. |
|
VI_ERROR_ASRL_OVERRUN |
An overrun error occurred during transfer. A character was not read from the hardware before the next character arrived. |
|
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 read operation synchronously transfers data. The file specified in fileName is opened in binary write-only mode. If the value of VI_ATTR_FILE_APPEND_EN is VI_FALSE, any existing contents are destroyed; otherwise, the file contents are preserved. The data read is written to the file. This operation returns only when the transfer terminates.
This operation is useful for storing raw data to be processed later.
Special Values for retCount Parameter
| Value | Action Description |
|---|---|
|
VI_NULL |
Do not return the number of bytes transferred. |
Related Topics