---
name: "SDL_TellIO"
section: "3"
platform: "linux"
package: "libsdl3-doc"
version: "3.2.10+ds-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/SDL_TellIO"
---

# SDL\_TellIO(3)

Determine the current read/write offset in an SDL\_IOStream data stream.

## NAME

SDL\_TellIO - Determine the current read/write offset in an  **SDL\_IOStream**\
  data stream.

## HEADER FILE

Defined in SDL3/SDL\_iostream.h

## SYNOPSIS

```
#include "SDL3/SDL.h"
```

**Sint64 SDL\_TellIO(SDL\_IOStream \*context);**

## DESCRIPTION

**SDL\_TellIO**\
  is actually a wrapper function that calls the

**SDL\_IOStream** **seek** method, with an offset of 0 bytes from  **SDL\_IO\_SEEK\_CUR** , to simplify application development.

## FUNCTION PARAMETERS

- *context*

  an  **SDL\_IOStream**\
    data stream object from which to get the current offset.

## RETURN VALUE

( **Sint64** ) Returns the current offset in the stream, or -1 if the information can not be determined.

## THREAD SAFETY

This function is not thread safe.

## AVAILABILITY

This function is available since SDL 3.2.0.

## SEE ALSO

**•**(3), [**SDL\_SeekIO**(3)](/SDL_SeekIO/3.md)