You can find this declaration in the generated Lexer include file:
MyLexer(QUEX_TYPE_CHARACTER* BufferMemoryBegin, size_t BufferMemorySize, QUEX_TYPE_CHARACTER* BufferEndOfContentP = 0x0, const char* CharacterEncodingName = 0x0, bool ByteOrderReversionF = false);
but it's not described on page 17 of the PDF documentation (0.50.1) nor the online version:
ByteOrderReversionF parameter is not described for all the constructors (I really don't know what this is.)
InputCodingName parameter is not described for all the constructors. (I presume it's something like "utf-8")
I presume that BufferMemoryBegin points to the first byte of the string being passed to the Lexer (although for me, it seems like I should make the pointer be one character BEFORE the start, so maybe I'm doing something wrong or maybe the usage isn't what I'm expecting.)
It's not clear whether BufferEndOfContentP points to the last character of the buffer or one pass the last character of the buffer.