Monitoring function for pointers (Checkpointer)
Use this function to monitor the memory access of pointers in runtime mode. As opposed
to other monitoring functions, a standard suggestion does not exist for the implementation
of CheckPointer. You must define an implementation according to your own requirements.
The CheckPointer function should check whether the returned pointer references a valid memory address;
monitors whether the orientation of the referenced memory range matches the variable
type that the pointer refers to. If both conditions are fulfilled, then the pointer
is returned. If not, then the function should complete an appropriate error handling.
CAUTION
To obtain the feature for monitoring functions, do not edit the declaration section. However, you are permitted to add local variables.
NOTICE
An implicit monitoring function call does not occur for THIS pointer and SUPER pointer.
NOTICE
For complier version 3.5.7.40 and later, the implicit check function “Checkpointer” also acts on REFERENCE variables in the same way as on pointer variables.
Model
Declaration:
// Automatically generated code: DO NOT EDIT FUNCTION CheckPointer : POINTER TO BYTE VAR_INPUT ptToTest : POINTER TO BYTE; iSize : DINT; iGran : DINT; bWrite: BOOL; END_VAR
Implementation: (incomplete)
// Not a standard implementation. Please add your own code here. CheckPointer := ptToTest;
When the function is called, CODESYS provides the following input parameters:
-
ptToTest: Target address of the pointer -
iSize: Size of the referenced variable; the data type ofiSizemust be compatible withINTand cover the dimensional scope of the variables. -
iGran: Granularity of the referenced size; this is the largest non-structured data type contained in the referenced variables; the data type ofiGranmust be compatible withINT -
bWrite: Access type (TRUE= write access,FALSE= read access); the data type ofbWritemust beBOOL
When the result of the check is positive, the unchanged pointer is returned (ptToTest).
See also