CString is:exact

A C string is a reference to an array of C characters terminated by NUL.
GHC C strings definitions (previously in GHC.Base). Use GHC.Exts from the base package instead of importing this module directly.
bool is whether whitespace is significant
MutByteArray representing null terminated c strings. All APIs in this module are unsafe and caution must be used when using them. Completely experimental. Everything is subject to change without notice.
C String literals
String