What is a NULL terminated string? I looked at this wiki article Null-terminated string :
But how can it be applied to DB2 for zOS??In computer programming, a null-terminated string is a character string stored as an array containing the characters and terminated with a null character ('\0', called NUL in ASCII). Alternative names are C string, which refers to the C programming language and ASCIIZ (note that C strings do not imply the use of ASCII).
The length of a C string is found by searching for the (first) NUL byte. This can be slow as it takes O(n) (linear time) with respect to the string length. It also means that a NUL cannot be inside the string, as the only NUL is the one marking the end.