P4032

Code

P4032

Message

Constant referenced in type parameter has no initializer

This error occurs when a constant name is used in a type parameter (such as a STRING length or array bound) but the referenced constant does not have an initializer value.

Example

The following code will generate error P4032:

VAR_GLOBAL CONSTANT
    MAX_LEN : INT;
END_VAR

FUNCTION_BLOCK MyFB
VAR_INPUT
    name : STRING[MAX_LEN];
END_VAR
END_FUNCTION_BLOCK

The constant MAX_LEN is declared without a value. To fix this error, provide an initializer:

VAR_GLOBAL CONSTANT
    MAX_LEN : INT := 100;
END_VAR

The same fix applies when the constant is used as an array bound. The declaration below triggers P4032 at the ARRAY declaration because CAPACITY has no value:

VAR_GLOBAL CONSTANT
    CAPACITY : INT;  (* No initializer *)
END_VAR

FUNCTION_BLOCK Ring
VAR
    slots : ARRAY[1..CAPACITY] OF INT;  (* Error: bound has no value *)
END_VAR
END_FUNCTION_BLOCK

Adding := 32 (or any integer literal) to CAPACITY resolves the error and lets the compiler determine the array’s size.

See Also

  • Initial Values — initializer syntax

  • STRING — STRING length parameter

  • Array Types — array bound expressions

  • P4008 — CONSTANT variable missing an initializer

  • P4030 — constant referenced in a type parameter is not defined

  • P4031 — constant referenced in a type parameter is not an integer type

References

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