---
name: "function::fastcall"
section: "3stap"
platform: "linux"
package: "systemtap-doc"
version: "5.1-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/function::fastcall"
---

# function::fastcall(3stap)

Mark function as declared fastcall

## NAME

function::fastcall - Mark function as declared fastcall

## SYNOPSIS

```
    fastcall()
```

## ARGUMENTS

None

## DESCRIPTION

Call this function before accessing arguments using the \*\_arg functions if the probed kernel function was declared fastcall in the source.

## SEE ALSO0

[*tapset::registers*(3stap)](/tapset::registers/3stap.md)