---
name: "std::_Not_fn"
section: "3cxx"
platform: "linux"
package: "libstdc++-12-doc"
version: "12.4.0-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/std::_Not_fn/3cxx"
---

# std::\_Not\_fn(3cxx)

Generalized negator.

## NAME

std::\_Not\_fn\< \_Fn \> - Generalized negator.

## SYNOPSIS

`#include <functional>`

### Public Member Functions

template\<**typename** **\_Fn2** \> constexpr **\_Not\_fn** (**\_Fn2** &&**\_\_fn**, int)\
 **\_Not\_fn** (**\_Not\_fn** &&**\_\_fn**)=**default**\
 **\_Not\_fn** (const **\_Not\_fn** &**\_\_fn**)=**default**\

### Public Attributes

template\<typename... \_Args\> constexpr **decltype**(\_S\_not\< \_\_inv\_res\_t\< \_Fn &&, \_Args... \> \>()) **operator()** (**\_Args** &&... **\_\_args**) &&noexcept(**\_\_is\_nothrow\_invocable**\< \_Fn &&, \_Args... \>::value &&noexcept(\_S\_not\< \_\_inv\_res\_t\< \_Fn &&, \_Args... \> \>()))\
 template\<typename... \_Args\> constexpr **decltype**(\_S\_not\< \_\_inv\_res\_t\< \_Fn &, \_Args... \> \>()) **operator()** (**\_Args** &&... **\_\_args**) &noexcept(**\_\_is\_nothrow\_invocable**\< \_Fn &, \_Args... \>::value &&noexcept(\_S\_not\< \_\_inv\_res\_t\< \_Fn &, \_Args... \> \>()))\
 template\<typename... \_Args\> constexpr **decltype**(\_S\_not\< \_\_inv\_res\_t\< \_Fn const &&, \_Args... \> \>()) **operator()** (**\_Args** &&... **\_\_args**) const &&noexcept(**\_\_is\_nothrow\_invocable**\< \_Fn const &&, \_Args... \>::value &&noexcept(\_S\_not\< \_\_inv\_res\_t\< \_Fn const &&, \_Args... \> \>()))\
 template\<typename... \_Args\> constexpr **decltype**(\_S\_not\< \_\_inv\_res\_t\< \_Fn const &, \_Args... \> \>()) **operator()** (**\_Args** &&... **\_\_args**) const &noexcept(**\_\_is\_nothrow\_invocable**\< \_Fn const &, \_Args... \>::value &&noexcept(\_S\_not\< \_\_inv\_res\_t\< \_Fn const &, \_Args... \> \>()))\

## Detailed Description

### template\<typename \_Fn\>

class std::\_Not\_fn\< \_Fn \>"Generalized negator.

## Author

Generated automatically by Doxygen for libstdc++ from the source code.