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calling a static function

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  • M Mark Salsbery

    steph5 wrote:

    it is being called from another source file in the project! I can't see any reason why it is aloud to do this.

    If it wasn't allowed, then all our source code would have to be in one file. Thankfully we have a linker to link separate compiled code modules :)

    steph5 wrote:

    In fact I have added my own class and function looking exactly the same and it gives me LNK 2019 error.

    To do its job, the linker needs to know where to find the code to link to. What's the complete error you're getting? Mark

    Mark Salsbery Microsoft MVP - Visual C++ :java:

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    toxcct
    wrote on last edited by
    #3

    Mark Salsbery wrote:

    If it wasn't allowed

    shouldn't it be: "if it weren't allowed" ? :confused: :)

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    • T toxcct

      Mark Salsbery wrote:

      If it wasn't allowed

      shouldn't it be: "if it weren't allowed" ? :confused: :)

      [VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

      M Offline
      M Offline
      Mark Salsbery
      wrote on last edited by
      #4

      :laugh: Probably. I'm a software engineer, dammit, not an English professor. :)

      Mark Salsbery Microsoft MVP - Visual C++ :java:

      T 1 Reply Last reply
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      • M Mark Salsbery

        :laugh: Probably. I'm a software engineer, dammit, not an English professor. :)

        Mark Salsbery Microsoft MVP - Visual C++ :java:

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        toxcct
        wrote on last edited by
        #5

        f*ck that, i'm french, not a native english speaker (like you) ! lol

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        • T toxcct

          Mark Salsbery wrote:

          If it wasn't allowed

          shouldn't it be: "if it weren't allowed" ? :confused: :)

          [VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

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          David Crow
          wrote on last edited by
          #6

          Not necessarily.

          "Love people and use things, not love things and use people." - Unknown

          "The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch

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          • M Mark Salsbery

            steph5 wrote:

            it is being called from another source file in the project! I can't see any reason why it is aloud to do this.

            If it wasn't allowed, then all our source code would have to be in one file. Thankfully we have a linker to link separate compiled code modules :)

            steph5 wrote:

            In fact I have added my own class and function looking exactly the same and it gives me LNK 2019 error.

            To do its job, the linker needs to know where to find the code to link to. What's the complete error you're getting? Mark

            Mark Salsbery Microsoft MVP - Visual C++ :java:

            S Offline
            S Offline
            steph5
            wrote on last edited by
            #7

            Hi I was in the understanding that if you declare a static function it can only be called from the source file where it is declared. Am I missing something?? The error says "unresolved external symbol" the call to the function is in file1.cpp where I have: myClass::myFunction(variable1, variable2); In myClass.h I have: class myClass { static void myFunction } and in myClass.cpp I have the function definition: myClass::myFunction() { //function definition } I can't call myFunction from file1.cpp As you can tell I am a novice programmer and in desperate need of explanation :(

            M C 2 Replies Last reply
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            • T toxcct

              f*ck that, i'm french, not a native english speaker (like you) ! lol

              [VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

              M Offline
              M Offline
              Mark Salsbery
              wrote on last edited by
              #8

              toxcct wrote:

              not a native english speaker (like you)

              LOL! I'm pretty sure the rest of the world doesn't call what we Americans speak "English" ;P

              Mark Salsbery Microsoft MVP - Visual C++ :java:

              J 1 Reply Last reply
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              • T toxcct

                Mark Salsbery wrote:

                If it wasn't allowed

                shouldn't it be: "if it weren't allowed" ? :confused: :)

                [VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

                M Offline
                M Offline
                Mark Salsbery
                wrote on last edited by
                #9

                Now that DavidCrow mentions it, and the caffeine is kicking in... I'm pretty sure I was right ;P LMAO

                Mark Salsbery Microsoft MVP - Visual C++ :java:

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                • T toxcct

                  Mark Salsbery wrote:

                  If it wasn't allowed

                  shouldn't it be: "if it weren't allowed" ? :confused: :)

                  [VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

                  C Offline
                  C Offline
                  CPallini
                  wrote on last edited by
                  #10

                  Nope. ;)

                  If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                  This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                  [My articles]

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                  • S steph5

                    Hi I was in the understanding that if you declare a static function it can only be called from the source file where it is declared. Am I missing something?? The error says "unresolved external symbol" the call to the function is in file1.cpp where I have: myClass::myFunction(variable1, variable2); In myClass.h I have: class myClass { static void myFunction } and in myClass.cpp I have the function definition: myClass::myFunction() { //function definition } I can't call myFunction from file1.cpp As you can tell I am a novice programmer and in desperate need of explanation :(

                    M Offline
                    M Offline
                    Mark Salsbery
                    wrote on last edited by
                    #11

                    steph5 wrote:

                    I was in the understanding that if you declare a static function it can only be called from the source file where it is declared. Am I missing something??

                    Yes :) That would make calling any external functions impossible.

                    steph5 wrote:

                    I can't call myFunction from file1.cpp

                    The linker can't find myClass.obj. Is myClass.cpp not part of the project? Mark

                    Mark Salsbery Microsoft MVP - Visual C++ :java:

                    1 Reply Last reply
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                    • S steph5

                      Hi I was in the understanding that if you declare a static function it can only be called from the source file where it is declared. Am I missing something?? The error says "unresolved external symbol" the call to the function is in file1.cpp where I have: myClass::myFunction(variable1, variable2); In myClass.h I have: class myClass { static void myFunction } and in myClass.cpp I have the function definition: myClass::myFunction() { //function definition } I can't call myFunction from file1.cpp As you can tell I am a novice programmer and in desperate need of explanation :(

                      C Offline
                      C Offline
                      CPallini
                      wrote on last edited by
                      #12

                      steph5 wrote:

                      I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.

                      That's true.

                      steph5 wrote:

                      Am I missing something??

                      Yes: in

                      steph5 wrote:

                      class myClass { static void myFunction }

                      is not an ordinary (i.e. C-style) static function, is a static method (i.e is a member of the class even if you don't need an instance of the class to call it). :)

                      If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                      This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                      [My articles]

                      M S R 3 Replies Last reply
                      0
                      • C CPallini

                        steph5 wrote:

                        I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.

                        That's true.

                        steph5 wrote:

                        Am I missing something??

                        Yes: in

                        steph5 wrote:

                        class myClass { static void myFunction }

                        is not an ordinary (i.e. C-style) static function, is a static method (i.e is a member of the class even if you don't need an instance of the class to call it). :)

                        If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                        This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                        [My articles]

                        M Offline
                        M Offline
                        Mark Salsbery
                        wrote on last edited by
                        #13

                        CPallini wrote:

                        That's true.

                        Huh? I call static methods that aren't in the same source file all the time :)

                        Mark Salsbery Microsoft MVP - Visual C++ :java:

                        S C 2 Replies Last reply
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                        • C CPallini

                          steph5 wrote:

                          I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.

                          That's true.

                          steph5 wrote:

                          Am I missing something??

                          Yes: in

                          steph5 wrote:

                          class myClass { static void myFunction }

                          is not an ordinary (i.e. C-style) static function, is a static method (i.e is a member of the class even if you don't need an instance of the class to call it). :)

                          If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                          This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                          [My articles]

                          S Offline
                          S Offline
                          steph5
                          wrote on last edited by
                          #14

                          Any ideas how I can have a function I can call from anywhere but where I don't need an instance of the class to call it?

                          M 1 Reply Last reply
                          0
                          • S steph5

                            Any ideas how I can have a function I can call from anywhere but where I don't need an instance of the class to call it?

                            M Offline
                            M Offline
                            Mark Salsbery
                            wrote on last edited by
                            #15

                            You can call a static method of a class from other cpp files! You need to link the files however. The problem is in your project - the linker isn't finding the file with the function being called. Fix that and it will work. The two files in your example ARE in the same project, right?

                            Mark Salsbery Microsoft MVP - Visual C++ :java:

                            S 1 Reply Last reply
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                            • M Mark Salsbery

                              CPallini wrote:

                              That's true.

                              Huh? I call static methods that aren't in the same source file all the time :)

                              Mark Salsbery Microsoft MVP - Visual C++ :java:

                              S Offline
                              S Offline
                              steph5
                              wrote on last edited by
                              #16

                              how?

                              M 1 Reply Last reply
                              0
                              • S steph5

                                how?

                                M Offline
                                M Offline
                                Mark Salsbery
                                wrote on last edited by
                                #17

                                ////////////////////////////
                                // myClass.h
                                ////////////////////////////

                                class myClass
                                {
                                public:
                                static void StaticMethod();
                                };

                                ////////////////////////////
                                // myClass.cpp
                                ////////////////////////////

                                void myClass::StaticMethod()
                                {
                                }

                                ////////////////////////////
                                // someother.cpp
                                ////////////////////////////

                                void somefunc()
                                {
                                myClass::StaticMethod();
                                }

                                Maybe you forgot the part in red above...

                                Mark Salsbery Microsoft MVP - Visual C++ :java:

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                                0
                                • M Mark Salsbery

                                  You can call a static method of a class from other cpp files! You need to link the files however. The problem is in your project - the linker isn't finding the file with the function being called. Fix that and it will work. The two files in your example ARE in the same project, right?

                                  Mark Salsbery Microsoft MVP - Visual C++ :java:

                                  S Offline
                                  S Offline
                                  steph5
                                  wrote on last edited by
                                  #18

                                  yes all the files are incluceded in the same project. how do I make sure the linker finds the file? The thing is I can call myClass::myFunction() from one of the .cpp files in the project, but I can't call it from another .cpp file in the same project. whats going on? Thanks for your time

                                  1 Reply Last reply
                                  0
                                  • C CPallini

                                    Nope. ;)

                                    If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                                    This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                                    [My articles]

                                    T Offline
                                    T Offline
                                    toxcct
                                    wrote on last edited by
                                    #19

                                    you're saying this as if such construction never exists... but I'm sure it is ! for example, the following is perfectly valid : "If I were you, I wouldn't do that"... ;P

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                                    M C 2 Replies Last reply
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                                    • M Mark Salsbery

                                      toxcct wrote:

                                      not a native english speaker (like you)

                                      LOL! I'm pretty sure the rest of the world doesn't call what we Americans speak "English" ;P

                                      Mark Salsbery Microsoft MVP - Visual C++ :java:

                                      J Offline
                                      J Offline
                                      john john mackey
                                      wrote on last edited by
                                      #20

                                      touché :laugh:

                                      1 Reply Last reply
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                                      • T toxcct

                                        you're saying this as if such construction never exists... but I'm sure it is ! for example, the following is perfectly valid : "If I were you, I wouldn't do that"... ;P

                                        [VisualCalc][Binary Guide][CommDialogs] | [Forums Guidelines]

                                        M Offline
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                                        Mark Salsbery
                                        wrote on last edited by
                                        #21

                                        Hey tox (aka Grammar Nazi)... Shouldn't you be busy working on this?[^] ;P

                                        Mark Salsbery Microsoft MVP - Visual C++ :java:

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                                        • M Mark Salsbery

                                          CPallini wrote:

                                          That's true.

                                          Huh? I call static methods that aren't in the same source file all the time :)

                                          Mark Salsbery Microsoft MVP - Visual C++ :java:

                                          C Offline
                                          C Offline
                                          CPallini
                                          wrote on last edited by
                                          #22

                                          Actually his sentence,

                                          steph5 wrote:

                                          I was in the understanding that if you declare a static function it can only be called from the source file where it is declared.

                                          and yours

                                          Mark Salsbery wrote:

                                          Huh? I call static methods that aren't in the same source file all the time

                                          are not in conflict: standard (i.e C-like, not belonging to a class) static functions have file scope, while static methods have not such a constraint. :)

                                          If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
                                          This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
                                          [My articles]

                                          T M 2 Replies Last reply
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