Closing a File :: Data Import and Export (Programming)

Programming

Closing a File

When you finish reading or writing, use fclose to close the file. For example, this line closes the file associated with file identifier fid:

```
status = fclose(fid);
```

This line closes all open files:

```
status = fclose('all'); 
```

Both forms return 0 if the file or files were successfully closed or -1 if the attempt was unsuccessful.

MATLAB automatically closes all open files when you exit from MATLAB. It is still good practice, however, to close a file explicitly with fclose when you are finished using it. Not doing so can unnecessarily drain system resources.

Note Closing a file does not clear the file identifier variable fid. However, subsequent attempts to access a file through this file identifier variable will not work.

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