The dynamic allocation program: values
Values are classified as follows:
- Keyword value
- Keyword values must be specified for some keywords. For example, the STATUS keyword may have a keyword value of SHR, NEW, MOD, or OLD (which can be abbreviated).
- String of key letters
- The value can be a string of letters in any order. The program does not check that the combination of letters provided is meaningful. For example, for the RECFM keyword, the value can be a string of letters from A, B, D, F, G, M, R, S, T, U, and V.
- Returned values
- No value should be provided by the terminal operator, because this keyword requests a value to be returned by the DYNALLOC information retrieval features. The further description refers to the kind of value that will be returned. This is usually in the form in which the operator would enter it, although in a few cases the value is as a hexadecimal string.
- Not allowed
- Some keywords do not require a value, and you must not provide one.
- Required
- A value must be provided if the keyword coded is designated as requiring a value.
- Optional
- Specification of a value is optional for some keywords.
- Single
- Only one value may be provided for some keywords.
- Multiple
- For some keywords, more than one value is permitted. (In some cases, DYNALLOC requires more than one value, although the dynamic allocation sample program does not enforce this.)
- Character string
- Any characters are permitted in this type of value, although in most cases there will be additional rules to follow, for example, for the DSNAME keyword.
- Numeric string
- Only numeric characters are allowed for this type of value, for example, for the EXPDT keyword.
- Maximum and minimum lengths
- For character and numeric values, the maximum and minimum lengths of the value are checked by the program. For a fixed-length string, these values are the same. The value is still passed to DYNALLOC as specified.
- Convertible to n byte binary
- A numeric value is required, of a magnitude representable in binary in the specified number of bytes. Values that are too large are truncated to the maximum possible for the width.
The dynamic allocation sample program does not support negative numbers. It does not cross-check operand keywords; errors of this type usually cause DYNALLOC to return error codes of the form 03xx.