Stratus Open VOS PL/I

Statements:

• • The % (Null) Statement

• The %do and %end Statements

The %do preprocessor statement introduces a %do-group; the %end preprocessor statement ends a %do-group. A %do-group contains one or more PL/I language statements (including null statements) and preprocessor statements that are evaluated during the first phase of compilation. A %do-group has the following syntax.

%do;

.

.

.

%end;

Note that iterative DOs are not allowed.

• • The %if Statement

The %if preprocessor statement evaluates an expression as true or false and controls subsequent compilation. The %if statement has the following syntax.

%if expression

%then statement

[%else statement]

The compiler evaluates expression to a scalar bit value. If expression is true (that is, the value is 1), the %thenexpression is false (the value is 0), compilation resumes with the %else clause or the next statement after the construct if no %else clause is specified. clause is compiled; if

IWithin expression, the operands can be decimal constants, bit constants, or character constants. If a %replace synonym is used in place of a constant, the synonym must have been previously defined within the compilation unit. (See The %replace Statement. later in this chapter, for more information on %replace.)

The following rules govern operand conversion in an %if expression.

• • For arithmetic operations, each operand is converted to fixed dec(5,0) before the operation is performed, and the result is converted to fixed dec(5,0). The null string is assigned the value 0 if it is converted to integer.

  • Any character value being converted to an arithmetic value must be an optionally signed integer.

  • Converting a fixed-point value to a bit value results in a bit string of length 17.

  • Converting a fixed-point decimal value to a character value results in a character string of length 8; leading zeros are replaced by spaces, and the rightmost space is replaced by a minus sign if the value is negative.

Like other PL/I conditional expressions, a PL/I-preprocessor conditional expression can use any arithmetic, relational, bit-string, or concatenate operator, with the exception of the exponentiation operator. The conditional expression cannot contain any function references, including references to built-in functions.

The statement following the %then or %else clause can be a preprocessor statement, a %do-group, or another PL/I statement that is suitable for use with a then or else PL/I language statement.

• • The %include Statement

The %include preprocessor statement inserts the contents of a text file into the program in place of the %include statement.

The %include statement has the following syntax.

%include 'file_name';

• The %list Statement

The %list preprocessor statement re-enables the compiler's listing option after it has been disabled by the %nolist%list statement has the following syntax. preprocessor statement. The

%list;

• The %nolist Statement

The %nolist preprocessor statement disables the compiler's listing option. The %nolist statement has the following syntax.

%nolist;

• • The %options Statement

The %options preprocessor statement specifies certain compiler options within the source module.

The %options statement has the following syntax.

You can specify the following compiler options in the %options statement.

• • default_char_set

  • mapcase or no_mapcase

    • max_fixed_bin

  • processor

  • system_programming or no_system_programming

  • untyped_storage_sharing

  • default_mapping or no_default_mapping

  • the following alignment options: longmap, shortmap, longmap_check, and shortmap_check

• The %page Statement

The %page preprocessor statement starts a new page in the compilation listing. The %page statement has the following syntax.

%page;

• The %replace Statement

The %replace preprocessor statement creates a synonym for a literal constant or declared name within a program. The %replace statement has the following syntax.

%replace synonym by