viReadToFile

NI-VISA 15.0 Help

Edition Date: June 2015

Part Number: 370131S-01

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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, 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.

Note Note  The retCount parameter always is valid on both success and error.


Related Topics

INSTR Resource

INTFC Resource

SERVANT Resource

SOCKET Resource

VI_ATTR_FILE_APPEND_EN

viRead

viWriteFromFile

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