Monitoring function for pointers (CheckPointer)
Use this function to monitor the memory access of pointers in runtime mode. As opposed
to other ⮫ monitoring functions, ⮫ 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 or not the passed pointer references a valid memory
address, and whether or not the orientation of the referenced memory area matches
the variable type to which the pointer refers. If both conditions are fulfilled, then
the pointer is returned. If not, then the function should complete an appropriate
error handling.
CAUTION
To get the feature for monitoring functions, do not edit the declaration part. However, you are permitted to add local variables.
NOTICE
An implicit monitoring function call does not occur for THIS pointer and SUPER pointer.
NOTICE
In compiler version 3.5.7.40 and higher, the “CheckPointer” also affects REFERENCE variables the same as pointer variables.
Template
Declaration:
// Automatisch erzeugter Code: NICHT EDITIEREN
FUNCTION CheckPointer : POINTER TO BYTE
VAR_INPUT
ptToTest : POINTER TO BYTE;
iSize : DINT;
iGran : DINT;
bWrite: BOOL;
END_VAR
Implementation: (incomplete)
// Keine Standardimplementierung. Bitte fügen Sie Ihren Code hier ein. CheckPointer := ptToTest;
When the function is called, it receives 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 ofbWritehas to beBOOL
When the result of the check is positive, the unchanged pointer is returned (ptToTest).