Escapes the nul characters in
string to “\x00”. It can be used
to compile a regex with embedded nul characters.
length can be -1 for a nul-terminated string.
In this case the output string will be of course equal to
Available since: 2.30
The string to escape.
The data is owned by the caller of the function. The value is a NUL terminated UTF-8 string.
The length of