Since they are non POD, their initialization happens at some indetermine time, and may result in data allocation, codec loading, and other unfortunate (and startup heavy) work. Change to use const char [] arrays, which are read only and shareable (no relocation needed). Only problem is in code that used to concatenate constants - otherwise the QString ctor taking a const char* is effective. One other slight problem would be that it can be difficult to have non ascii string constants (need L"foo" or the like). Contacts library should compile with QT_ASCII_CAST_WARNINGS with no warnings now.