boost::urls::grammar::operator‐ :: Boost Libraries Documentation

# boost::urls::grammar::operator‐

Return a new character set by subtracting

## Synopsis

Declared in `<boost/url/grammar/lut_chars.hpp>`

    constexpr
    lut_chars
    operator‐(
        lut_chars const& cs0,
        lut_chars const& cs1) noexcept;

## Description

This function returns a new character set which is formed from all of the characters in `cs0` which are not in `cs`.

## Example

This statement declares a character set containing all the lowercase letters which are not vowels:

    constexpr lut_chars consonants = lut_chars("abcdefghijklmnopqrstuvwxyz") - "aeiou";

## Complexity

Constant.

## Return Value

The new character set.

## Parameters

Name | Description
cs0 | A character set to join.
cs1 | A character set to join.

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