# fsIOGetFileSize<no value>
The **fsIOGetFileSize** function is used to get the size of an opened file.

 

##### Syntax

``` wasm
unsigned long long fsIOGetFileSize(
    FsIOFile file
);
```

 

##### Members

{{< table-wrapper >}}

| Parameters | Description                                                         |
|------------|---------------------------------------------------------------------|
| `file`     | This is the ID of a file, as returned by one of the open functions. |

{{< /table-wrapper >}}


 

##### Return Values

The size of the file, in bytes. This may be 0 if there is an error, ie: the file is not opened, or is too too big.

 

##### Remarks

It is important to be aware that while the size is returned is a 64bits integer, the WASM API can only read up too 2^32 bytes. However even *that* upper limit is not realistic and will probably not enter into the WASM memory modules, so for optimal both performance and memory usage, please **limit the size of the read** from files.