TDMS_OpenFileEx
- Updated2023-02-21
- 2 minute(s) read
int TDMS_OpenFileEx (char *filePath, int readOnly, unsigned int options, TDMSFileHandle *file);
Purpose
Opens a file handle for an existing TDM Streaming file. Pass the file handle to other TDM Streaming Library functions to read or modify the file contents. Call TDMS_SaveFile to save file modifications to disk.
Call the TDMS_CloseFile function to close the file handle when you finish using the file.
Parameters
| Input | ||
| Name | Type | Description |
| filePath | char * | The path to the file that will be opened. If this value is not an absolute pathname, then the pathname is relative to the current working directory. |
| readOnly | int | Specify a nonzero value or select True in the function panel to allow only read access to the file. Specify 0 or select False in the function panel to allow read and write access to the file. If the current user does not have write privileges for the file or if the file is marked read-only, pass a nonzero value for this parameter. |
| options | unsigned int | Pass TDMS_OpenFileDisableBuffering if you want the TDM Streaming Library to write to and read from this file without Windows system buffering. By disabling system buffering you can speed up data transfers in certain situations. If you have a small amount of data to transfer you might not notice a difference if you disable buffering. If the file is located on a Redundant Array of Independent Disks (RAID), consider accessing the file without buffering to speed up data transfers. The TDMS_OpenFileDisableBuffering option is only supported on Windows operating systems and when using version 2.0 or later of the TDM Streaming file format. Pass TDMS_OpenFileDoNotCreateIndexFile if you do not want the TDM Streaming Library to create an index file. An index file is a separate file with the same basename and a .tdms_index file extension that contains summary information from the .tdms file. In some situations an index file can speed up access to the .tdms file contents. If an index file already exists this flag will have no effect. To specify two or more flags, combine them with the bitwise OR operator as shown: TDMS_OpenFileDisableBuffering | TDMS_OpenFileDoNotCreateIndexFile To specify none of the flags, pass 0. |
| Output | ||
| Name | Type | Description |
| file | TDMSFileHandle | The handle for the TDM Streaming file. Pass this handle to TDM Streaming Library functions that require a file. Call TDMS_SaveFile to save the file to disk. Call TDMS_CloseFile to close the file handle when you finish using the file. |
Return Value
| Name | Type | Description |
| status | int | Return value indicating whether the function was successful. Unless otherwise stated, zero represents successful execution and a negative number represents the error code. Error codes are defined in cvi\include\cvitdms.h. |
Additional Information
Library: TDM Streaming Library
Include file: cvitdms.h
LabWindows/CVI compatibility: LabWindows/CVI 2009 and later
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