PVS-Studio warning V542 for Miranda IM

static void
sttRegisterToolBarButton(..., char * pszButtonName, ...)
{
  ...
  if ((BYTE)pszButtonName)
    tbb.tbbFlags=TBBF_FLEXSIZESEPARATOR;
  else
    tbb.tbbFlags=TBBF_ISSEPARATOR;
  ...
}

This code is suspicious. In fact, we check that the string address is multiple of 256. But what the programmer actually wanted to write in the condition is a mystery. I'm not sure that this is exactly an error. There are similar games with pointers - that is, something else is stored in pointers. This code should be cited simply as an example of a suspicious code fragment that needs checking.

This suspicious code was found in Miranda IM project by PVS-Studio static code analyzer.
Warning message is:
V542 Consider inspecting an odd type cast: 'char *' to 'char'.  clist_modern  modern_toolbar.cpp  586

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/