PVS-Studio warning V547 for amtsdk

static char* _username = "";
static char* _password = "";
static char* _host = "";
static char* _hostMask = "";

if (((_username == "") && (_password != "")) ||
    ((_username != "") && (_password == "")))

This code is dangerous and incorrect. But sometimes it will work - when the whole code is in one module (one *.obj). The compiler will create only one empty string in memory.

This suspicious code was found in amtsdk project by PVS-Studio static code analyzer.
Warning message is:
V547 Expression '_username == ""' is always false. To compare strings you should use strcmp() function. Discovery discoverysample.cpp 184

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