%STR Used to Store Null-Terminated String

When used on the left-hand side of an expression, %STR(ptr:length) assigns the value of the right-hand side of the expression to the storage pointed at by the pointer, adding a null-terminating byte at the end. If the length specified as the second parameter of %STR is N, then at most N-1 bytes of the right-hand side can be used, since 1 byte must be reserved for the null-terminator at the end.

The maximum length that can be specified is 65535. This means that at most 65534 bytes of the right-hand side can be used, since 1 byte must be reserved for the null-terminator at the end.

The length indicates the amount of storage that the pointer points to. This length should be greater than the maximum length the right-hand side will have. The pointer must be set to point to storage at least as long as the length parameter. If the length of the right-hand side of the expression is longer than the specified length, the right-hand side value is truncated.

Note:
Data corruption will occur if both of the following are true:
  1. The length parameter is greater than the actual length of data addressed by the pointer.
  2. The length of the right-hand side is greater than or equal to the actual length of data addressed by the pointer.
If you are dynamically allocating storage for use by %STR, you must keep track of the length that you have allocated.
Figure 254. %STR (left-hand-side) Examples 
 *..1....+....2....+....3....+....4....+....5....+....6....+....7...+....
D String1         S               *
D Fld1            S             10A

 /FREE
     %str(String1: 25)= 'abcdef';
     // The storage pointed at by String1 now contains 'abcdef¬'
     // Bytes 8-25 following the null-terminator are unchanged.
 
     %str (String1: 4) = 'abcdef';
     // The storage pointed at by String1 now contains 'abc¬'
 /END-FREE

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