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error C2678

Scheduled Pinned Locked Moved C / C++ / MFC
linuxregexhelplearning
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  • _ _Flaviu

    Thank you Richard, that error has vanished, but I cannot try this code yet ... why do you say that this solution is not really correct ? The safe solution would be to overload |= operator, but I cannot do that into enum, right ?

    L Offline
    L Offline
    Lost User
    wrote on last edited by
    #6

    _Flaviu wrote:

    why do you say that this solution is not really correct ?

    Because, as I mentioned before, enums are used to indicate a set of possible values for an item. For example a class of type Car could contain an enum that indicates the manufacturer, such that the enum definition is:

    enum manufacturer
    {
    AUDI = 1,
    BMW,
    DAIMLER,
    MERCEDES,
    // etc.
    }

    And you would never combine thos values in the car type variable. So, in your case you should use #define statements, which the compiler will be happy with.

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    0
    • L Lost User

      _Flaviu wrote:

      why do you say that this solution is not really correct ?

      Because, as I mentioned before, enums are used to indicate a set of possible values for an item. For example a class of type Car could contain an enum that indicates the manufacturer, such that the enum definition is:

      enum manufacturer
      {
      AUDI = 1,
      BMW,
      DAIMLER,
      MERCEDES,
      // etc.
      }

      And you would never combine thos values in the car type variable. So, in your case you should use #define statements, which the compiler will be happy with.

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      _Flaviu
      wrote on last edited by
      #7

      But this enum is not a part of any struct or class, is just defined into a header file, along with other several enum's ... and this enum has a lot of values, that is why I intend to avoid to translated as #define's ... I don't know what to do ...

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      0
      • _ _Flaviu

        But this enum is not a part of any struct or class, is just defined into a header file, along with other several enum's ... and this enum has a lot of values, that is why I intend to avoid to translated as #define's ... I don't know what to do ...

        L Offline
        L Offline
        Lost User
        wrote on last edited by
        #8

        But the issue is, as I keep repeating, that this is not the correct way to use enums. If you want to combine flag values then use #define, if you want to select one value from a set then use enum. That is the rule for C and C++, and that is why the compiler complains about your code.

        _ 1 Reply Last reply
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        • L Lost User

          But the issue is, as I keep repeating, that this is not the correct way to use enums. If you want to combine flag values then use #define, if you want to select one value from a set then use enum. That is the rule for C and C++, and that is why the compiler complains about your code.

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          _Flaviu
          wrote on last edited by
          #9

          Thank you Richard for your patience. BTW, is a legacy code, is not written by me. There will be more suitable to chnage this enum to a struct and where to overload |= operator ?

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          • _ _Flaviu

            Thank you Richard for your patience. BTW, is a legacy code, is not written by me. There will be more suitable to chnage this enum to a struct and where to overload |= operator ?

            L Offline
            L Offline
            Lost User
            wrote on last edited by
            #10

            Why would you change it to a struct, it only requires a single integer variable to hold all the flags.

            int flags = FILE_READONLY | FILE_HIDDEN;
            flags |= FILE_SYSTEM;

            _ 2 Replies Last reply
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            • L Lost User

              Why would you change it to a struct, it only requires a single integer variable to hold all the flags.

              int flags = FILE_READONLY | FILE_HIDDEN;
              flags |= FILE_SYSTEM;

              _ Offline
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              _Flaviu
              wrote on last edited by
              #11

              So the finest solution is to take these values from enum and put them as #defines. I will do this change.

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              • L Lost User

                Why would you change it to a struct, it only requires a single integer variable to hold all the flags.

                int flags = FILE_READONLY | FILE_HIDDEN;
                flags |= FILE_SYSTEM;

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                _Flaviu
                wrote on last edited by
                #12

                I am afraid that I cannot change that enum into #defines, because I have:

                na->flags |= flag;

                where

                FILE_FLAGS flag;

                and na is struct level1, and inside this level1 struct, I have

                struct level1
                {
                FILE_FLAGS flags;
                ....
                };

                I have entered in some deadlock ? Please help me to solve this error ...

                V L 2 Replies Last reply
                0
                • _ _Flaviu

                  I am afraid that I cannot change that enum into #defines, because I have:

                  na->flags |= flag;

                  where

                  FILE_FLAGS flag;

                  and na is struct level1, and inside this level1 struct, I have

                  struct level1
                  {
                  FILE_FLAGS flags;
                  ....
                  };

                  I have entered in some deadlock ? Please help me to solve this error ...

                  V Offline
                  V Offline
                  Victor Nijegorodov
                  wrote on last edited by
                  #13

                  Try to declare both flags and flag as int

                  _ 1 Reply Last reply
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                  • V Victor Nijegorodov

                    Try to declare both flags and flag as int

                    _ Offline
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                    _Flaviu
                    wrote on last edited by
                    #14

                    Yes, but FILE_FLAGS is enum with int values ...

                    V 1 Reply Last reply
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                    • _ _Flaviu

                      Yes, but FILE_FLAGS is enum with int values ...

                      V Offline
                      V Offline
                      Victor Nijegorodov
                      wrote on last edited by
                      #15

                      Then, as Richard already suggested replace this enum with a set of #define.

                      _ 1 Reply Last reply
                      0
                      • V Victor Nijegorodov

                        Then, as Richard already suggested replace this enum with a set of #define.

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                        _Flaviu
                        wrote on last edited by
                        #16

                        Agree, but that enum is a part of another struct ... so, how can I put as part of a struct several #defines ?

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                        0
                        • _ _Flaviu

                          I am afraid that I cannot change that enum into #defines, because I have:

                          na->flags |= flag;

                          where

                          FILE_FLAGS flag;

                          and na is struct level1, and inside this level1 struct, I have

                          struct level1
                          {
                          FILE_FLAGS flags;
                          ....
                          };

                          I have entered in some deadlock ? Please help me to solve this error ...

                          L Offline
                          L Offline
                          Lost User
                          wrote on last edited by
                          #17

                          Of course you can change it to #defines. The definition of FILE_FLAGS then becomes an int type. And then the rest of the code should compile correctly.

                          _ 1 Reply Last reply
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                          • L Lost User

                            Of course you can change it to #defines. The definition of FILE_FLAGS then becomes an int type. And then the rest of the code should compile correctly.

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                            _Flaviu
                            wrote on last edited by
                            #18

                            I am not get something, so forgive me. I have moved those enum values as #defines, but of course, now I get error from struct: doesn't know who is FILE_FLAGS flags; from level1 struct.

                            /*
                            typedef enum {
                            FILE_READONLY = 0x00000001,
                            FILE_HIDDEN = 0x00000002,
                            FILE_SYSTEM = 0x00000004,

                            FILE\_DIRECTORY = 0x00000010,
                            FILE\_ARCHIVE = 0x00000020,
                            FILE\_DEVICE = 0x00000040,
                            FILE\_NORMAL = 0x00000080,
                            
                            FILE\_TEMPORARY = 0x00000100,
                            

                            ....
                            .....

                            }FILE_FLAGS;
                            */

                            #define FILE_READONLY = 0x00000001
                            #define FILE_HIDDEN = 0x00000002
                            #define FILE_SYSTEM = 0x00000004

                            of course, FILE_FLAGS enum has disappeared ... obviously, I don't understood something ... but what ?

                            struct level1
                            {
                            FILE_FLAGS flags; // <-- error
                            ....
                            };

                            V L 2 Replies Last reply
                            0
                            • _ _Flaviu

                              I am not get something, so forgive me. I have moved those enum values as #defines, but of course, now I get error from struct: doesn't know who is FILE_FLAGS flags; from level1 struct.

                              /*
                              typedef enum {
                              FILE_READONLY = 0x00000001,
                              FILE_HIDDEN = 0x00000002,
                              FILE_SYSTEM = 0x00000004,

                              FILE\_DIRECTORY = 0x00000010,
                              FILE\_ARCHIVE = 0x00000020,
                              FILE\_DEVICE = 0x00000040,
                              FILE\_NORMAL = 0x00000080,
                              
                              FILE\_TEMPORARY = 0x00000100,
                              

                              ....
                              .....

                              }FILE_FLAGS;
                              */

                              #define FILE_READONLY = 0x00000001
                              #define FILE_HIDDEN = 0x00000002
                              #define FILE_SYSTEM = 0x00000004

                              of course, FILE_FLAGS enum has disappeared ... obviously, I don't understood something ... but what ?

                              struct level1
                              {
                              FILE_FLAGS flags; // <-- error
                              ....
                              };

                              V Offline
                              V Offline
                              Victor Nijegorodov
                              wrote on last edited by
                              #19

                              _Flaviu wrote:

                              struct level1 { FILE_FLAGS flags; // <-- error .... };

                              Try

                              struct level1
                              {
                              int flags; // <-- error
                              ....
                              };

                              _ 1 Reply Last reply
                              0
                              • V Victor Nijegorodov

                                _Flaviu wrote:

                                struct level1 { FILE_FLAGS flags; // <-- error .... };

                                Try

                                struct level1
                                {
                                int flags; // <-- error
                                ....
                                };

                                _ Offline
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                                _Flaviu
                                wrote on last edited by
                                #20

                                Ok, but even flag is comming as function parameter, just like this:

                                static void SomeFunction(level1* na, FILE_FLAGS flag)
                                {
                                ....
                                na->flags |= ~flag;
                                ....
                                }

                                So, I guess I cannot give up FILE_FLAGS enum ... don't I ?

                                V 1 Reply Last reply
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                                • _ _Flaviu

                                  Ok, but even flag is comming as function parameter, just like this:

                                  static void SomeFunction(level1* na, FILE_FLAGS flag)
                                  {
                                  ....
                                  na->flags |= ~flag;
                                  ....
                                  }

                                  So, I guess I cannot give up FILE_FLAGS enum ... don't I ?

                                  V Offline
                                  V Offline
                                  Victor Nijegorodov
                                  wrote on last edited by
                                  #21

                                  Change this parameter to be

                                  static void SomeFunction(level1* na, int flag)
                                  {

                                  1 Reply Last reply
                                  0
                                  • _ _Flaviu

                                    I am not get something, so forgive me. I have moved those enum values as #defines, but of course, now I get error from struct: doesn't know who is FILE_FLAGS flags; from level1 struct.

                                    /*
                                    typedef enum {
                                    FILE_READONLY = 0x00000001,
                                    FILE_HIDDEN = 0x00000002,
                                    FILE_SYSTEM = 0x00000004,

                                    FILE\_DIRECTORY = 0x00000010,
                                    FILE\_ARCHIVE = 0x00000020,
                                    FILE\_DEVICE = 0x00000040,
                                    FILE\_NORMAL = 0x00000080,
                                    
                                    FILE\_TEMPORARY = 0x00000100,
                                    

                                    ....
                                    .....

                                    }FILE_FLAGS;
                                    */

                                    #define FILE_READONLY = 0x00000001
                                    #define FILE_HIDDEN = 0x00000002
                                    #define FILE_SYSTEM = 0x00000004

                                    of course, FILE_FLAGS enum has disappeared ... obviously, I don't understood something ... but what ?

                                    struct level1
                                    {
                                    FILE_FLAGS flags; // <-- error
                                    ....
                                    };

                                    L Offline
                                    L Offline
                                    Lost User
                                    wrote on last edited by
                                    #22

                                    Add this line somewhere before the first reference to FILE_FLAGS :

                                    typedef int FILE_FLAGS;

                                    _ 1 Reply Last reply
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                                    • L Lost User

                                      Add this line somewhere before the first reference to FILE_FLAGS :

                                      typedef int FILE_FLAGS;

                                      _ Offline
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                                      _Flaviu
                                      wrote on last edited by
                                      #23

                                      I encounter another error if I made these modifications:

                                      data->com = na->flags & ATTR_IS_COMPRESSED; // <-- error C2059: syntax error : '='

                                      (where data->com is int) because now ATTR_IS_COMPRESSED is #define, not part of enum FILE_FLAGS ...

                                      L 2 Replies Last reply
                                      0
                                      • _ _Flaviu

                                        I encounter another error if I made these modifications:

                                        data->com = na->flags & ATTR_IS_COMPRESSED; // <-- error C2059: syntax error : '='

                                        (where data->com is int) because now ATTR_IS_COMPRESSED is #define, not part of enum FILE_FLAGS ...

                                        L Offline
                                        L Offline
                                        Lost User
                                        wrote on last edited by
                                        #24

                                        What is data->com?

                                        _Flaviu wrote:

                                        because now ATTR_IS_COMPRESSED is #define, not part of enum FILE_FLAGS

                                        That is not the reason. I can only assume that you have done a partial change and some parts of your code are still incorrect. If you still have the FILE_FLAGS enum then it is going to cause problems. It would probably help if you showed all the code portions that are connected. It is difficult to be certain of the answers when looking at only a single line of code.

                                        1 Reply Last reply
                                        0
                                        • _ _Flaviu

                                          I encounter another error if I made these modifications:

                                          data->com = na->flags & ATTR_IS_COMPRESSED; // <-- error C2059: syntax error : '='

                                          (where data->com is int) because now ATTR_IS_COMPRESSED is #define, not part of enum FILE_FLAGS ...

                                          L Offline
                                          L Offline
                                          Lost User
                                          wrote on last edited by
                                          #25

                                          I still cannot see enough information. Please provide what I previously requested and reply to this message. Please do not email me personally.

                                          _ 3 Replies Last reply
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