Built-in functions

REXX provides a rich set of built-in functions, including character manipulation, conversion, and information functions.

There are six other built-in functions that TSO/E provides: EXTERNALS, FIND, INDEX, JUSTIFY, LINESIZE, and USERID. If you plan to write REXX programs that run on other SAA environments, note that these functions are not available to all the environments. In this section, these six built-in functions are identified as non-SAA functions.

In addition to the built-in functions, TSO/E also provides TSO/E external functions that you can use to perform different tasks. These functions are described in TSO/E external functions. The following are general notes on the built-in functions:

The parentheses in a function are always needed, even if no arguments are required. The first parenthesis must follow the name of the function with no space in between.
The built-in functions work internally with NUMERIC DIGITS 9 and NUMERIC FUZZ 0 and are unaffected by changes to the NUMERIC settings, except where stated. This is not true for RANDOM.
Any argument named as a string may be a null string.
If an argument specifies a length, it must be a positive whole number or zero. If it specifies a start character or word in a string, it must be a positive whole number, unless otherwise stated.
Where the last argument is optional, you can always include a comma to indicate you have omitted it; for example, DATATYPE(1,), like DATATYPE(1), would return NUM.
If you specify a pad character, it must be exactly one character long. (A pad character extends a string, usually on the right. For an example, see the LEFT built-in function on page LEFT.)
If a function has an option you can select by specifying the first character of a string, that character can be in upper- or lowercase.
A number of the functions described in this chapter support DBCS. A complete list and descriptions of these functions are in Double-byte character set (DBCS) support.