< cpp‎ | regex
Defined in header <regex>
class regex_error;
(since C++11)

Defines the type of exception object thrown to report errors in the regular expressions library.

cpp/error/exceptioncpp/error/runtime errorstd-regex error-inheritance.svg

Inheritance diagram

Member functions

constructs a regex_error object
(public member function)
gets the std::regex_constants::error_type for a regex_error
(public member function)

Inherited from std::exception

Member functions

destroys the exception object
(virtual public member function of std::exception)
returns an explanatory string
(virtual public member function of std::exception)


#include <regex>
#include <iostream>
int main()
    try {
        std::regex re("[a-b][a");
    catch (const std::regex_error& e) {
        std::cout << "regex_error caught: " << e.what() << '\n';
        if (e.code() == std::regex_constants::error_brack) {
            std::cout << "The code was error_brack\n";

Possible output:

regex_error caught: The expression contained mismatched [ and ].
The code was error_brack