ADR
The operator is an extension of the IEC 61131-3 standard.
ADR delivers the address of its argument in a PVOID or, depending on the runtime system, in a DWORD (32-bit systems) or LWORD (32 and 64-bit systems). To ensure independence from the runtime system architecture, it is recommended to use PVOID as data type.
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Shifting the contents of addresses by Online Change If you use an online change, contents of addresses may shift. As a result, POINTER variables could point to an invalid memory area. In order to avoid problems, make sure that TwinCAT updates the value of pointers when an online change takes place. |
Syntax:
VAR
<address name> : PVOID | DWORD | LWORD | __XWORD | POINTER TO < basis data type>;
END_VAR
<address name> := ADR(<variable name>);
Samples:
ST:
nVar := ADR(bVAR);
FBD:
Sample with different data types:
FUNCTION_BLOCK FB_Address
VAR
nVar : INT := 10;
pNumber : POINTER TO INT;
nAddress1 : PVOID;
nAddress2 : DWORD;
nAddress3 : LWORD;
nAddress4 : __XWORD;
END_VAR
pNumber := ADR(nVar); // pNumber wird der Adresse von nVar zugewiesen
nAddress1 := ADR(nVar); // PVOID : für 32- und 64-Bit-Systeme
nAddress2 := ADR(nVar); // DWORD : nur für 32-Bit-Systeme
nAddress3 := ADR(nVar); // LWORD : für 32- und 64-Bit-Systeme
nAddress4 := ADR(nVar); // __XWORD : für 32- und 64-Bit-Systeme
See also: