---
title: "sec_protocol_options_set_tls_is_fallback_attempt(_:_:)"
framework: security
role: symbol
role_heading: Function
path: "security/sec_protocol_options_set_tls_is_fallback_attempt(_:_:)"
---

# sec_protocol_options_set_tls_is_fallback_attempt(_:_:)

## Declaration

```swift
func sec_protocol_options_set_tls_is_fallback_attempt(_ options: sec_protocol_options_t, _ is_fallback_attempt: Bool)
```

## Parameters

- `options`: A sec_protocol_options_t instance.
- `is_fallback_attempt`: Set a flag indicating that this is a TLS fallback attempt.

## Discussion

Discussion Signal if this is a TLS fallback attempt.  A fallback attempt is one following a previously failed TLS connection  due to version or parameter incompatibility, e.g., when speaking to a server  that does not support a client-offered ciphersuite.

Clients MUST NOT enable fallback for fresh connections.