http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59421
Bug ID: 59421 Summary: stof(), stod() wrong result Product: gcc Version: 4.8.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: libstdc++ Assignee: unassigned at gcc dot gnu.org Reporter: stefan.helm...@t-online.de sometimes: y = stod(str); // with str = "0" cout << y << endl; prints out: 0.4167 It depends on where the executable is copied to. It does not depend on optimisation level. I use c++11. workaround: y = stod(""+str+""); Windows 7 64 bit, mingw-builds/x64-4.8.1-posix-seh-rev5