Statements

This chapter describes how to use OpenFrame PL/I statements.

1. ALLOCATE Statement (Abbreviation: ALLOC)

The ALLOCATE statement allocates storage for controlled or based variables.

1.1. ALLOCATE Statement for Controlled Variables

The ALLOCATE statement allocates storage for controlled variables. Controlled parameters can also be allocated. An ALLOCATE statement can describe the array bounds and string length of a controlled variable.

figure syntax allocate controlled
ALLOCATE Statement for Controlled Variables

Array bounds and string lengths are evaluated when an ALLOCATE statement is executed.

  • An ALLOCATE statement or a DECLARE or DEFAULT statement must specify required size and string length information.

  • If the DIMENSION attribute or a string length are specified in an ALLOCATE statement, they will override attributes specified during a variable declaration.

  • If a bound or string length is specified as an asterisk (*) in an ALLOCATE statement, the information of the current generation will be used. If there is no current generation, the information will be undefined and a program error will occur.

  • The DIMENSION attribute specified in an ALLOCATE statement must match the number of declared dimensions. That is, n DIMENSION attributes must be specified for an n-dimensional array.

  • The BIT, CHARACTER, and GRAPHIC attributes must be the same as the attributes declared in a DECLARE statement.

The following example uses an ALLOCATE statement:

  DCL X(M,N) CHAR(L) CTL;
  M = 10;
  N = 5;
  L = 100;
  ALLOCATE X(5,5) CHAR(200);

1.2. ALLOCATE Statement for Based Variables

The ALLOCATE statement allocates storage for based variables and saves a storage address to a locator variable.

figure syntax allocate based
ALLOCATE Statement for Based Variables

Allocated storage size is determined according to a based variable’s attributes and the length and the size determined when the ALLOCATE statement is executed.

2. ASSIGN Statement

The assignment statement evaluates an expression and assigns a result value to one or more target variables. If a target or pseudo variable attributes are different from source attributes, data conversion will be required.

figure syntax assignment
ASSIGN Statement
Component Description

reference

A target or pseudo variable.

expression

A source expression.

BY NAME

An option used in a structure assignment. For more information, refer to "Assignment Execution".

Compound Assignment Statement

A compound assignment statement uses compound assignment operations.

figure syntax assignment compound
Compound Assignment Statement
Component Description

reference

Target variable or pseudo variable.

compound operator

Operator to apply to the source and target before the assignment is made.

Compound operators that can be used in an assignment statement are:

  • +=: Add and then assign

  • -=: Subtract and then assign

  • *=: Multiply and then assign

  • /=: Divide and then assign

  • **=: Exponentiate and then assign

  • ||=: Concatenate and then assign

  • |=: or and then assign

  • &=: and and then assign

  • ^= or <>: exclusive-or and then assign

expression

Expression of the source.

The following are examples of executing compound assignment statements.

 X += 5;      ==> X = X + 5;
 X *= Y - 1;  ==> X = X * (Y - 1);

Target Variables

Target variables can be elements, arrays, structures, or pseudo variables.

  • Array

    • A target variable must be an array of scalars or structures. A source must be a scalar expression or an expression with the same number of dimensions and the same bounds as a target.

  • Structure

    • If BY NAME is specified, each target and source must be a structure.

    • If BY NAME is not specified, each target must be a structure and each source must be a scalar or a structure that is the same as a target.

    • If BY NAME is not specified and a source is described as a NULL string("") then:

      1. all targets will be padded with '00’X.

      2. all numeric targets will 0.

      3. all character and graphic targets will be padded with blanks.

Assignment Execution

  • Array

    • All array operands (of sources and targets) must have the same number of dimensions and the same bounds.

    • An array assignment is expanded into a loop as follows:

       DO I1 = LBOUND( target-variable, 1 ) to HBOUND( target-variable, 1 );
 DO I2 = LBOUND( target-variable, 2 ) to HBOUND( target-variable, 2 );
...
 DO IN = LBOUND( target-variable, N ) to HBOUND( target-variable, N );

   generated element assignment ;

 END;

    • N is the number of dimensions of a target. In the generated element assignment, I1 through IN are used as subscripts. If a source is scalar, subscripts will not be used.

  • Structure

    • If BY NAME is not specified:

      • All operands must be the same structure, not an array. The member of a structure can be an array.

      • An assignment will be executed on each member. If the number of members is n, assignments will be executed n times.

      • If a member is an aggregate, assignments will be executed on all members of the member.

    • If BY NAME is specified:

      1. The same name as the name of a target structure member will be searched from a source from the first member. The members will be direct children of the structure, not children of a child of the structure.

      2. A search will be repeated until a same name is found.

      3. If a searched member is a structure or an array of structures, an assignment with the BY NAME option will be executed.

      4. If a searched member is a scalar or an array of scalars, an element assignment will be executed.

      5. The above steps will be repeated for following members.

    • The following is an example of a structure assignment using BY NAME:

       DCL 1 ONE,              DCL 1 TWO,              DCL 1 THREE
       2 PART1,                2 PART1,                2 PART1,
         3 RED,                  3 BLUE,                 3 RED,
         3 ORANGE,               3 GREEN,                3 BLUE,
       2 PART2,                  3 RED,                  3 BROWN,
         3 YELLOW,             2 PART2,                2 PART2,
         3 BLUE,                 3 BROWN,                3 YELLOW,
         3 GREEN;                3 YELLOW;               3 GREEN;

3. BEGIN Statement

A BEGIN statement specifies the start of one or more blocks.

figure syntax begin
BEGIN statement

4. CALL Statement

A CALL statement calls a subroutine.

figure syntax call
CALL statement
Component Description

entry-reference

Subroutine name.

generic-name

Variable name declared as GENERIC.

built-in name

Built-in function name.

argument

List of arguments to pass into the subroutine.

5. CLOSE Statement

The CLOSE statement closes a specified file.

figure syntax close
CLOSE Statement
Component Description

FILE

File to close. Use an asterisk (*) to close all open files.

6. DECLARE Statement

The DECLARE statement specifies a data item’s name and some or all attributes. If the attributes are not declared explicitly and cannot be determined by context, default attributes will be used.

figure syntax declare
DECLARE Statement
Component Description

*

Cannot be used for the names of scalar and level-1 data.

attributes

Data attributes in any order. For more information, refer to Data Types and Attributes.

level

Positive integer. The default level of scalar or array data is level-1.

name

Data name. A level-1 name must be unique in a block.

Condition prefixes and labels must not be specified in a DECLARE statement.

7. DEFAULT Statement (Abbreviation: DFT)

The DEFAULT statement defines data-attribute defaults when a set of attributes is not complete.

Attributes to which a DEFAULT statement for implicit, contextual, and partially-complete declarations are not applied are determined by language-specified defaults.

A DEFAULT statement redefines all attributes except for a name declared with the ENTRY or FILE attributes. However, the CONSTANT attribute is applied implicitly to a name without attributes that implies the VARIABLE attribute by PL/I before the DEFAULT statement is applied.

figure default stmt1
DEFAULT Statement

identifiers:

image

Component Description

RANGE(identifier)

Defaults to apply to names that start with the same letter.

RANGE(identifier : identifier)

Defaults to apply to names that start with one of the letters between the letters specified when using two identifiers.

RANGE(*)

Defaults to apply to all names in the scope of a DEFAULT statement.

DESCRIPTORS

Defaults to apply to attributes included in the description of a parameter in a parameter description list of an explicit Entry declaration. At least one attribute must exist. DESCRIPTORS will not be applied to NULL descriptions.

attribute_specification

  • attribute-list

    Required only to complete a data item declaration. If FILE is used, the VARIABLE and INTERNAL attributes can be used. A dimension attribute can be defined as the first item in an attribute specification. The default value of the dimension attribute can be applied only to explicitly declared names. The bounds can be specified as an arithmetic constant or an expression and can include the REFER option. An INITIAL attribute can be specified.

  • VALUE

    Can come anywhere in attribute_specification except before a dimension attribute.

    The VALUE attribute defines the size of an area, string length, or numeric precision. The size, length, and precision in a VALUE clause are applied before the system defaults for them are applied.

    The following is an example:

    DEFAULT RANGE(I) VALUE(FIXED DECIMAL(7,3));
I = 2;

    If it is not declared explicitly, I will have FIXED BINARY(15,0) attributes because of its language-specified defaults. Since the DEFAULT statement specifies default precision (7,3) only for the names with the FIXED DECIMAL attribute, the statement will not influence I.

Multiple DEFAULT statements can be used in a block. The scope of a DEFAULT statement is the block in which the statement is declared, all blocks within the block that do not include another DEFAULT statement with the same range, and all blocks that are not contained in a block with a DEFAULT statement with the same range.

A DEFAULT statement affects only names declared explicitly in an internal block because the scope of an implicit declaration is determined implicitly as if the names were declared implicitly using a DECLARE statement when the names immediately follows a PROCEDURE statement of an external procedure.

The following is an example:

 X: PROC;
 LABEL1: DEFAULT RANGE(AB) FLOAT;
  Y: BEGIN;
 LABEL2: DEFAULT RANGE(ABC) FIXED;
 END X;

The scope of the DEFAULT statement of LABEL1 is the procedure X and begin-block Y included in the procedure. The scope specified by the DEFAULT statement of LABEL1 are all names that start with AB and are declared in the procedure X and begin-block Y. However, the names that start with ABC and declared in begin-block Y are excluded and can be used only within begin-block Y.

8. DEFINE Statement

The DEFINE statement specifies an alias for a PL/I data type or defines an ordinal data type.

8.1. DEFINE ALIAS Statement

The DEFINE ALIAS statement specifies an alias for PL/I data type.

figure syntax define alias
DEFINE ALIAS statement
Component Description

alias-name

Alias name.

attributes

Attributes that can be specified for the data type of the alias.

The following is an example of using the DEFINE ALIAS statement to define an alias and using it to declare a variable.

  DEFINE ALIAS NAME CHAR(32);
  DECLARE COMPANY_NAME TYPE NAME;

8.2. DEFINE ORDINAL Statement

The DEFINE ORDINAL statement defines an ordinal data type.

figure syntax define ordinal
DEFINE ORDINAL statement

ordinal-value-list:

image

Component Description

ordinal-name

Name of the ordinal type.

member

Name of a member of the ordinal type.

VALUE

Value of a member of the ordinal type.

  • If VALUE is specified, it must be an integer value greater than that of the previous member.

  • If VALUE is omitted for the first member, 0 is used. If VALUE is omitted for any other members, the next greater integer is used (previous member’s value + 1).

PRECISION

Precision of VALUE. If PRECISION is omitted, PRECISION is determined by the range of VALUE.

SIGNED, UNSIGNED

Specifies VALUE as SIGNED or UNSIGNED.

The following is an example of using the DEFINE ORDINAL statement to define an ordinal data type and using it to declare a variable.

  DEFINE ORDINAL LANG ( PLI, COBOL, ASSEMBLER, C, CPP );
  DECLARE COMPILER ORDINAL LANG;

9. DELAY Statement

The DELAY statement suspends program execution for a specified period of time.

figure syntax delay
DELAY Statement
Component Description

expression

Time to suspend. (Unit: milliseconds)

10. DELETE Statement

The DELETE statement deletes a record from a file.

figure syntax delete
DELETE Statement
Component Description

FILE

File that includes a record to delete. The file must have the UPDATE attribute.

KEY

Record that corresponds with a specified KEY is removed. To use the KEY option, the file must have the DIRECT or SEQUENTIAL KEYED attributes.

11. DISPLAY Statement

The DISPLAY statement displays messages on stdout.

figure syntax display
DISPLAY Statement
Component Description

expression

If necessary, this expression is converted to a character string and the converted string will be displayed. However, GRAPHIC strings are not converted.

12. DO Statement

The DO statement defines conditions for repeated execution on a multiple statements groups. A DO statement must be used along with an END statement. Statements between a DO statement and an END statement are grouped as a do-group.

A DO statement can be one of the following types:

  • Type 1

  • Type 2

  • Type 3

  • Type 4

Type 1

Type 1 defines a do-group and executes statements within the do-group. Type 1 does not define conditions for repeated execution.

figure syntax do type1
DO Statement Type 1

Type 2 and Type 3

Type 2 and Type 3 define a do-group and executes statements within the do-group. They can define conditions for repeated execution.

Type 2:

figure syntax do type2
DO Statement Type 2

Type 3:

figure syntax do type3
DO Statement Type 3

specification:

image

Component Description

WHILE(expression)

Evaluates an expression and converts it to a BIT string before executing a do-group.

If any BIT in a string are 1, a do-group will be executed. If all BITs are 0 or a string is NULL, a do-group will not be executed.

If there are multiple specifications, the next specification will be executed.

UNTIL(expression)

Evaluates an expression and converts it to a BIT string after executing a do-group.

If all BITs in a string are 0 or the string is NULL, a do-group will be executed. If any BIT is 1, a do-group will not be executed.

If there are multiple specifications, the next specification will be executed.

reference

The value of expression1 will be used for initialization before executing a do-group.

If there are multiple specifications, each specification’s value of expression1 will be used for initialization.

expression1

Initial value of a reference.

If TO, BY, and REPEAT are omitted, the value of expression1 will always be used for initialization.

TO expression2

The end value of a reference. If a value of a reference is not in the range of values between expression1 and expression2, a corresponding do-group will be ended.

If TO expression2 is omitted, a do-group will be ended by the WHILE or UNTIL options.

BY expression

Increment to a reference. A reference is added by the value of an expression after executing a do-group.

If TO expression2 is specified and BY expression is omitted, BY 1 will be the default value.

UPTHRU expression

The end value of a reference. A reference is increased by 1 and saved after executing a do-group.

The TO option is compared before executing a do-group but the UPTHRU option is compared after executing a do-group. Therefore, the UPTHRU option allows a do-group to be executed at least once.

DOWNTHRU expression

The end value of a reference. A reference is subtracted by 1 and saved after executing a do-group.

The TO option is compared before executing a do-group but the DOWNTHRU option is compared after executing a do-group. Therefore, the DOWNTHRU option allows a do-group to be executed at least once.

REPEAT expression

The expression is evaluated, the result value is saved to a reference, and a do-group is executed.

A do-group execution is repeated until ended by the WHILE or UNTIL options.

Type 4

Type 4 defines a do-group and executes statements within the do-group repeatedly and infinitely.

figure syntax do type4
DO Statement Type 4
Component Description

FOREVER

Same as LOOP.

LOOP

Sets infinite repetition.

To end the repetition, use a GOTO or LEAVE statement or end the procedure or program.

13. END Statement

An END statement specifies the end of one or more blocks or groups. Every block or group must have an END statement.

figure syntax end
END statement
Component Description

statement-label

Label of the nearest preceding DO, SELECT, PACKAGE, BEGIN or PROCEDURE statement before the END statement to indicate the end of a block or group. If omitted, the END statement closes the nearest preceding block or group.

14. ENTRY Statement

All non-pointer parameters of any procedures that include an ENTRY statement must be BYADDR (pass by address).

figure syntax entry
ENTRY statement
Component Description

entry-label

Additional entry point name of the procedure.

parameter-list

Parameters of the entry point.

returns-options

RETURNS option of the entry point.

15. EXIT Statement

The EXIT statement ends a currently running PL/I program. In OpenFrame PL/I, this statement is the same as a STOP statement.

figure syntax exit
EXIT Statement

16. FETCH Statement

The FETCH statement loads a procedure or program dynamically if its entry-point is not in memory.

figure syntax fetch
FETCH Statement
Component Description

entry-constant

Name of a procedure or program to load.

17. FLUSH Statement

The FLUSH statement flushes the buffer of a specified file. To use a FLUSH statement for a file, the file must have the BUFFERED attribute.

figure syntax flush
FLUSH Statement
Component Description

FILE

File to flush. Use an asterisk (*) to flush all open files.

18. FORMAT Statement

The FORMAT statement specifies a format list used for an edit-directed I/O.

figure syntax format
FORMAT Statement
Component Description

label

Label to be specified by an R-format item. For more information, refer to R-format.

format list

Format list used for an edit-directed I/O.

19. FREE Statement

The FREE statement releases storage allocated for controlled and based variables.

19.1. FREE Statement for Controlled Variables

The FREE statement releases storage allocated for controlled variables.

figure syntax free controlled
FREE Statement for Controlled Variables

19.2. FREE Statement for Based Variables

The FREE statement releases storage allocated for based variables.

figure syntax free based
FREE Statement for Based Variable

20. GET Statement

The GET statement reads records from a stream that can be fetched from a dataset or string.

When reading data from a dataset, the syntax of the GET statement is as follows:

figure syntax get file
GET FILE Statement
Component Description

FILE

Target file. (Default value: SYSIN file)

data-specification

Refer to Data Specification.

COPY

Saves a copy of the fetched stream in the specified file. If no file is specified, the copy is saved in the SYSPRINT file.

SKIP (expression)

Sets an expression value and skips the amount of data set, then reads the data after the skipped data. (Default value: 1)

When reading data from a string, the syntax of the GET statement is as follows:

figure syntax get string
GET STRING Statement
Component Description

STRING

Target string.

data-specification

Refer to Data Specification.

21. GOTO Statement

The GOTO statement moves the program control to the position specified by a label.

figure syntax goto
GOTO Statement
Component Description

label

Label constant or variable.

If a label is a variable, the value at the point in time when the GOTO statement is executed will be referred to.

A GOTO statement can be used to move a control to a label within a same block or an outer block. A control can also be moved from an ON-unit to an outer block.

A GOTO statement cannot be used in the following cases:

  • To an outer procedure from an inner procedure.

  • To an inner block or procedure from an outer block or procedure.

  • To a FORMAT statement.

22. IF Statement

The IF statement evaluates a condition and selects an action according to the result.

figure syntax if
IF Statement
Component Description

expression

Expression that has a true or false result.

Multiple conditions can be specified using '&' and '|'.

unit

Statements to be executed according to a condition result.

A unit can be a single statement, a do-group, or a begin-block.

If a condition is true, a unit described in THEN will be executed. If false, a unit described in ELSE will be executed, or the IF statement will be terminated when ELSE is not used.

23. ITERATE Statement

The ITERATE statement skips a running do-group and executes the next do-group with an iteration condition.

An ITERATE statement must be used within a do-group.

figure syntax iterate
ITERATE Statement
Component Description

label-constant

Must be the label of a DO statement. If omitted, the most recent do-group with an ITERATE statement will be skipped.

24. LEAVE Statement

The LEAVE statement ends a running do-group. This statement must be used within a do-group.

figure syntax leave
LEAVE Statement
Component Description

label-constant

Must be the label of a DO statement. If omitted, the most recent do-group with a LEAVE statement will be terminated.

25. LOCATE Statement

The LOCATE statement specifies the location of an output buffer using a pointer to enable access to the buffer through a based variable.

figure syntax locate
LOCATE Statement
Component Description

FILE

Target file with a OUTPUT SEQUENTIAL BUFFERED attribute.

based variable

Based variable that enables access to an output buffer.

SET

Pointer to which the address of an output buffer is saved.

KEYFROM

Key of a record to write.

To use the KEYFROM option, a file must have the KEYED attribute.

The value of KEYFROM is converted to a CHARACTER in an indexed dataset or a FIXED DECIMAL in a relative dataset.

A record will be written when a buffer is flushed using a FLUSH statement, or when the next LOCATE statement is executed, not when a LOCATE statement is executed. Therefore, a record to be written to a dataset can be modified using a based variable even if a LOCATE statement is executed.

26. NULL Statement

The NULL statement executes nothing. In general, this statement is used to perform nothing when THEN, ELSE, WHEN, or OTHER is used.

figure syntax null
NULL Statement

27. ON Statement

The ON statement registers an ON-unit to execute when a specified condition occurs.

figure syntax on
ON Statement
Component Description

condition

One or more conditions. For more information, refer to Conditions.

SNAP

Not supported.

SYSTEM

Default action for a condition. For more information, refer to Conditions.

ON-unit

Statements to execute when a condition occurs.

An ON-unit can be a single statement or a begin-block.

An ON-unit is executed when a corresponding condition is met, not when an ON statement is executed.

If a specified condition occurs, an ON-unit will be executed. If a same condition is specified multiple times, the ON-unit of the last ON statement will be executed. Conditions specified using an ON statement are released when a block or procedure with the ON statement is terminated or by a user using a REVERT statement.

The following example registers the ZERODIVIDE condition:

 ON ZERODIVIDE
 BEGIN;
 DISPLAY('The ZERODIVIDE condition occurs.');
 END;

 A = B / 0;

The ZERODIVIDE condition occurs when a division by 0 is attempted. The condition occurs due to "A = B / 0", so that the DISPLAY statement is executed because an ON-unit registered through the ON statement is executed.

28. OPEN Statement

The OPEN statement opens a specified file.

figure syntax open
OPEN Statement

open-options:

image

Component Description

FILE

File to open.

FILE attribute

Refer to File.

TITLE

DD name of an external dataset described in a JCL.

LINESIZE

Length of a line. (Default value: 120)

If a stream length exceeds LINESIZE, the next line will be used from the first column.

This option can be used only for STREAM OUTPUT files.

PAGESIZE

Number of lines in a page. (Default value: 60)

If a line exceeds PAGESIZE, the ENDFILE condition will occur.

A new page can start using a PAGE format item or the PAGE option in a PUT statement.

A file can be opened explicitly by using an OPEN statement. An unopened file opens when using a READ, WRITE, REWRITE, DELETE, LOCATE, PUT, or GET statement.

A FILE attribute that was defined during a declaration can be redefined by defining the attribute when explicitly opening a file using an OPEN statement. The following example redefines the FILE attribute using an OPEN statement.

 DECLARE TEST FILE RECORD OUTPUT;
 OPEN FILE(TEST) STREAM INPUT;
 CLOSE FILE(TEST);

 OPEN FILE(TEST);

In the first OPEN statement, TEST has the STREAM and INPUT attributes. Once a file is closed, the FILE attribute is lost and not applied when the file is reopened. Therefore, in the second OPEN statement, TEST has the RECORD and OUTPUT attributes specified in the DECLARE statement.

If the FILE attribute defined during declaration is different from the attribute defined during opening, an error will occur.

29. OTHERWISE Statement

For information about the OTHERWISE statement, refer to SELECT Statement.

30. PACKAGE Statement

A PACKAGE statement can only include variable declarations, DEFAULT statements, and procedure blocks. OpenFrame PL/I currently only supports procedure blocks in a PACKAGE statement and does not support PACKAGE statement options.

figure syntax package
PACKAGE statement
Component Description

condition_prefix

Condition prefix that applies to all procedures of a package. For more information, refer to the description of Condition Prefix in Conditions.

package_name

Package name.

31. PUT Statement

The PUT statement creates a record of saves as a stream that can be saved to a dataset or string.

When saving data to a dataset, the syntax of the PUT statement is as follows:

figure syntax put file
PUT FILE Statement
Component Description

FILE

Target file. (Default value: SYSIN file)

data-specification

Refer to Data Specification.

SKIP (expression)

Sets a number of lines to skip. (Default value: 1)

LINE (expression)

Sets a value of lines to move.

To use the LINE option, a file must have the PRINT attribute.

PAGE

Starts a new page. The default start line value is 1.

To use the PAGE option, a file must have the PRINT attribute.

When saving data to a string, the syntax of the PUT statement is as follows:

figure syntax put string
PUT STRING Statement
Component Description

STRING

Target string.

data-specification

Refer to Data Specification.

32. READ Statement

The READ statement reads records from a dataset. The read record can be saved to a variable or pointed by a pointer.

figure syntax read
READ Statement
Component Description

FILE

File to read. The file must have the INPUT or UPDATE attributes.

IGNORE

Sets a value for the number of records to be ignored.

If an evaluated expression value is n and the IGNORE option is used, the (n+1)th record will be read.

INTO

Saves a read record to a specified variable. If the variable is an array or a structure, it must be assigned to storage.

SET

Specified pointer that points to a read record.

KEY

Record that corresponds to a specified KEY to be read.

To use the KEY option, the file must have the DIRECT or SEQUENTIAL KEYED attribute.

KEYTO

Reads a record’s key value when a record is read.

To use the KEYTO option, a file must have the SEQUENTIAL KEYED attribute.

33. RETURN Statement

A RETURN statement terminates the execution of a procedure and the control is returned to the calling code.

figure syntax return
RETURN statement

  • A RETURN statement with an expression cannot be used within a procedure with OPTIONS(MAIN).

  • A RETURN statement without an expression cannot be used within a procedure with RETURNS options.

  • A procedure with RETURNS options must have one or more RETURN statements.

34. REVERT Statement

The REVERT statement unregisters an ON-unit that was registered using an ON statement.

figure syntax revert
REVERT Statement
Component Description

condition

One or more conditions. For more information, refer to Conditions.

A REVERT statement only unregisters an ON-unit registered in a current block or procedure and cannot unregister an ON-unit registered in an upper block or procedure. If there is no ON-unit registered in a current block or procedure, a REVERT statement will not be executed.

The following example unregisters an ON-unit by using a REVERT statement:

 ON ZERODIVIDE
 BEGIN;
 DISPLAY('ZERODIVIDE condition raised');
 END;

 REVERT ZERODIVIDE;

 A = B / 0;

The ZERODIVIDE condition occurs due to "A = B / 0;" but the ON-unit registered using the ON statement is not executed because it has been unregistered by using the REVERT statement. If there is no registered ON-unit, a default action is executed according to a condition; either the ERROR condition occurs or the program execution continues. The ZERODIVIDE condition set an ERROR condition as the default action.

35. REWRITE Statement

The REWRITE statement updates a record in a dataset.

figure syntax rewrite
REWRITE Statement
Component Description

FILE

File to update. The file must have the UPDATE attribute.

FROM

Variable to which a record is saved. If the variable is an array or a structure, it must be assigned to storage.

KEY

Record that corresponds to a specified KEY is updated.

To use the KEY option, the file must have the DIRECT or SEQUENTIAL KEYED attributes.

36. SELECT Statement

The SELECT statement evaluates a condition and then selects a branch according to the result from multiple branches.

A SELECT statement can include one or more WHEN statements and either zero or one OTHERWISE statements. A SELECT statement must be paired with an END statement.

figure syntax select
SELECT Statement
Component Description

SELECT (expression)

Expression to be evaluated and saved.

WHEN (expression) unit

There can be one or more expressions. To specify multiple expressions, separate each expression with '&' or '|' as delimiter. Each expression is evaluated and compared with the expression value of a SELECT statement.

If any of the expression values are the same as the expression value of a SELECT statement, the unit is executed.

OTHERWISE unit

If all the expression values in a WHEN statement are different from the expression value of a SELECT statement, the OTHERWISE statement will be executed.

If there is no OTHERWISE statement, the SELECT statement will terminate.

unit

Statements to be executed if the WHEN or OTHERWISE statement is met.

A unit can be a single statement, a do-group, or a begin-block.

37. SIGNAL Statement

The SIGNAL statement causes a condition to enable a user to execute an ON-unit.

figure syntax signal
SIGNAL Statement
Component Description

condition

Condition. For more information, refer to Conditions.

If an ON-unit is registered by a user, the ON-unit will be executed. If there are none, a default action specified internally will be executed.

In the following example, an ON-unit using a SIGNAL statement has been executed:

 ON ZERODIVIDE
 BEGIN;
 DISPLAY('ZERODIVIDE condition occurs.');
 END;

 SIGNAL ZERODIVIDE;

The ON-unit of the ZERODIVIDE condition is executed because of the SIGNAL statement. Even though a condition related to I/O has occurred, the corresponding ON-unit is not executed if the relevant files are different.

38. STOP statement

The STOP statement ends a currently running PL/I program. In OpenFrame PL/I, this statement is the same as an EXIT statement.

figure syntax stop
STOP Statement

39. WHEN Statement

For information about the WHEN statement, refer to SELECT Statement.

40. WRITE Statement

The WRITE statement writes a record to a dataset.

figure syntax write
WRITE Statement
Component Description

FILE

File to write. The file must have the OUTPUT or UPDATE attributes.

FROM

Variable to which a record is written. If the variable is an array or a structure, it must be assigned to storage.

KEYFROM

Key of a record to write.

To use the KEYFROM option, a file must have the KEYED attribute.

The value of KEYFROM is converted to a CHARACTER in an indexed dataset, or a FIXED DECIMAL in a relative dataset.

KEYTO

Key of the next record to write.

To use the KEYTO option, a file must have the SEQUENTIAL KEYED attribute.