Apple’s Xcode and std::getline

Anyone writing C++ code will want to read in a file and do something with the data contained within. That is usually simple:

#include <iostream>
#include <fstream>
using namespace std;
int main () {
	ifstream readfile("example.txt", ifstream::in);
	string line;
	if(!in.is_open()){
		cerr << "File not found!" << endl;
	} 	else {
	 	getline(readfile,line);
		cout << line << endl;
	}
	readfile.close();
	return 0;
}

For some reason that no one seems to comprehend Xcode sets preprocessor flags which are inconsistent with the standard libraries it ships with. Specifically:

_GLIBCXX_DEBUG=1
_GLIBCXX_DEBUG_PEDANTIC=1

Fortunately this can be easily fixed on a per-project basis by removing the offending lines from Project>>Edit Active Target “…”>>Preprocessor Macros. The easiest way to find it is to search for ‘preprocessor’ in the Active Target configuration. It should look something like the image below when done.

A more pervasive and lasting solution is to edit the project templates in ‘/Developer/Library/Xcode/Project Templates.’ You can find exactly which template are offending using the following command:

find '/Developer/Library/Xcode/Project Templates' -name "project.pbxproj" -exec grep -l "_GLIBCXX_DEBUG=1" \{\} \;

You will want to remove the two offending definitions in code that resembles that below:

GCC_PREPROCESSOR_DEFINITIONS = (
	"_GLIBCXX_DEBUG=1",
	"_GLIBCXX_DEBUG_PEDANTIC=1",
);

Hope this saves others time.

Advertisement