Why does this C++11 std::regex example throw a regex_error exception?
28,519
Thanks for the hint. Had no idea the regex code in g++ was incomplete.
In the meantime, guess we'll have to refer to this old StackOverflow question:
C++: what regex library should I use?
Author by
Stéphane
Linux, Ubuntu, C++ developer. https://www.linkedin.com/in/scharette http://www.ccoderun.ca/
Updated on July 09, 2022Comments
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Stéphane almost 2 years
Trying to learn how to use the new std::regex in C++11. But the example I tried is throwing a regex_error exception I don't understand. Here is my sample code:
#include <iostream> #include <regex> int main() { std::string str = "xyzabc1xyzabc2xyzabc3abc4xyz"; std::regex re( "(abc[1234])" ); // <-- this line throws a C++ exception // also tried to do this: // std::regex re( "(abc[1234])", std::regex::optimize | std::regex::extended ); while ( true ) { std::cout << "searching in " << str << std::endl; std::smatch match; std::regex_search( str, match, re ); if ( match.empty() ) { std::cout << "...no more matches" << std::endl; break; } for ( auto x : match ) { std::cout << "found: " << x << std::endl; } str = match.suffix().str(); } return 0; }
I compile and run like this:
g++ -g -std=c++11 test.cpp ./a.out terminate called after throwing an instance of 'std::regex_error' what(): regex_error
Looking at the backtrace in gdb, I see the exception thrown is
regex_constants::error_brack
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ACyclic over 9 yearsFirst gcc support is in gcc 4.9 : stackoverflow.com/questions/23474121/…