_CP_SLEN returns the length of the CPSTR*, string.
Syntax
int _CP_SLEN(CPSTR* string)
Warning: The _CP_SLEN() macro
should never be used to change the length of a CPSTR. Doing so can
cause data corruption.
Example(s)
CPSTR * s = _CP_mkstr("hi");
int i = _CP_SLEN(s);