Misra Rule 11.2

This is a discussion on Misra Rule 11.2 within the C Programming forums, part of the General Programming Boards category; Hi I am not sure if many of you are aware of what the Misra C 2004 standards are but ...

  1. #1
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    Apr 2006
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    Misra Rule 11.2

    Hi

    I am not sure if many of you are aware of what the Misra C 2004 standards are but rule 11.2 states

    Rule 11.2 (required) Conversions shall not be performed between a pointer to object and any other than an integral type, another pointer to object type or a pointer to void.


    I am looking for opinions of what you think this actually means!

    for example this would be a violation
    Code:
    float *x;
    long y;
    
    x=&y; /*Violation*/
    however would the below code be a violation?

    Code:
    long *x;
    int y;
    
    x=&y; /*Violation*/
    It produces a compiler warning using Dev C++ but the Misra rule seems to state that it is ok to convert between integral types.

    I hope I have been clear enough!
    Last edited by hammer1234; 04-06-2006 at 06:05 AM.

  2. #2
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    depends on the size of int and long -- if they are both the same size it would be ok, but not if they are different sizes. If a long = 4 bytes and an int = 2 bytes, then dereferencing the long pointer would produce unpredictible results. The safest way to do it is to declare the pointer the same data type as the object to which it points -- the pointer should be int* in your example.

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