PQescapeLiteral in Libpq

I'm using the libpq.dll libraries to connect to postgress. When I issue a call to PQescapeLiteral with a file path as the argument, the result string seems to always start with a bogus " E". For example, "C:\MyFile" is returned as " E'C:\\:MyFile'" (not including the double quotes). Is this a normal result or can't PQescapeLiteral be used to escape a file path literal? If not, are there any functions that can be used to "escape" a file path?

 

Thanks, Lynn