---
name: "struct_ff_envelope"
section: "9"
platform: "linux"
package: "linux-manual-3.2"
version: "3.2.78-1"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/struct_ff_envelope"
---

# struct\_ff\_envelope(9)

generic force-feedback effect envelope

## NAME

struct\_ff\_envelope - generic force-feedback effect envelope

## SYNOPSIS

```
struct ff_envelope {
  __u16 attack_length;
  __u16 attack_level;
  __u16 fade_length;
  __u16 fade_level;
};
```

## MEMBERS

attack\_length

duration of the attack (ms)

attack\_level

level at the beginning of the attack

fade\_length

duration of fade (ms)

fade\_level

level at the end of fade

## DESCRIPTION

The *attack\_level* and *fade\_level* are absolute values; when applying envelope force-feedback core will convert to positive/negative value based on polarity of the default level of the effect. Valid range for the attack and fade levels is 0x0000 - 0x7fff

## COPYRIGHT