Thread: <regex> portability issue

I'm trying to parse a text file written in a certain format to be used in a game. I felt C++11/14's new regex library would be suitable.

I did a minimal test program. I've not done the functionality in the switch-case clause yet, but rather focused on getting the totals of various elements (monsters/spells/items...) first to see if that works before moving on.

The code below compiles and works as I intended using GCC 6.1.1 on Linux. However, compiling the same code unaltered with my MinGW cross compiler and running it on WINE, it prints nothing but a line break. I tried compiling the code again in MSVC 2015 with the same result.

I have no platform specific code, so I'm stumped as to why it behaves differently on MinGW/MSVC compiled EXEs.

The syntax of the text file goes like this (eg.):

Code:

LANGUAGE {English/ANSI}
ITEMTOT {32}
INAM1 {sword}
INAM2 {shield}

Code:

#include <fstream>
#include <iostream>
#include <regex>
#include <string>

bool parseScript(const char * filename)
{
	std::ifstream scriptFile(filename);
	std::regex labelSyntax("([A-Z]+)([0-9]*)[ \t]+\\{(.*)\\}[\r\n]");
	std::string line;
	
	while (std::getline(scriptFile, line))
	{
		std::smatch m;
		if (std::regex_match(line, m, labelSyntax))
		{
			if (m[1] == "LANGUAGE")
				std::cout << "Locale set to " << m[3] << std::endl;
			else if (m[1] == "ITEMTOT")
				std::cout << "There are " << m[3] << " total items." << std::endl;
			else if (m[1] == "SPLTOT")
				std::cout << "There are " << m[3] << " total spells." << std::endl;
			else if (m[1] == "MOBTOT")
				std::cout << "There are " << m[3] << " total monsters." << std::endl;
			else if (m[1] == "WEPTOT")
				std::cout << "There are " << m[3] << " total weapons." << std::endl;
			else if (m[1] == "BARTOT")
				std::cout << "There are " << m[3] << " total barriers." << std::endl;
			else if (m[1] == "TRPTOT")
				std::cout << "There are " << m[3] << " total traps." << std::endl;
			else if (m[1] == "TRETOT")
				std::cout << "There are " << m[3] << " total treasures." << std::endl;
			else if (m[1] == "TELTOT")
				std::cout << "There are " << m[3] << " total teleports." << std::endl;
			else
			{
				switch (m[1].str()[0])
				{
					case 'I': // item
						break;
					case 'S': // spell
						break;
					case 'M': // monster
						break;
					case 'W': // weapon
						break;
					case 'B': // barrier
						break;
					case 'X': // trap
						break;
					case 'T': // treasure
						break;
					case 'P': // teleport
						break;
					case 'L': // level
						break;
					default:
						std::cerr << "Error: Unknown label" << std::endl;
						return false;
				}
			}
		}
	}
	scriptFile.close();
	return true;
}

int main(int argc, char ** argv)
{
	if (argc != 2)
	{
		std::cerr << "Usage: " << argv[0] << " <input file>" << std::endl;
		return 1;
	}
	parseScript(argv[1]);
	return 0;
}

I had the same problem some time ago.
GCC 4.9 was the first version with substantially working regex - https://gcc.gnu.org/gcc-4.9/changes.html

MinGW might be an old version.
Even if it isn't, it relies heavily on the Microsoft runtime (which is itself broken).

You'd have to check the detailed documentation for MSVC to find out what is supported (or when/if it will be supported).
It might be one of those "pony up some money to get a non-broken compiler".

That stinks. Regex's been in the standard for 4-5 years now. Microsoft must be really lazy... I have MinGW's GCC at 6.1.1 as well.

Boost.Regex yields the same result too, unfortunately. I have no idea what to do... Here's the changed code:

Code:

#ifdef _WIN32
	#include <boost/regex.hpp>
#else
	#include <regex>
#endif // _WIN32

bool parseScript(const char * filename)
{
	std::ifstream scriptFile(filename);
#ifdef _WIN32
	boost::regex labelSyntax("([A-Z]+)([0-9]*)[ \t]+\\{(.*)\\}[\r\n]");
#else
	std::regex labelSyntax("([A-Z]+)([0-9]*)[ \t]+\\{(.*)\\}[\r\n]");
#endif // _WIN32
	std::string line;
	
	while (std::getline(scriptFile, line))
	{
#ifdef _WIN32
		boost::smatch m;
		if (boost::regex_match(line, m, labelSyntax))
#else
		std::smatch m;
		if (std::regex_match(line, m, labelSyntax))
#endif // _WIN32