#include <stdio.h

#include <conio.h

#include <iostream.h

//

// marks a location in the program for resume

// does not return control, exits function from inside macro

//

// yield( x, ret )

//      x : the 'name' of the yield, cannot be ambiguous in the

//          function namespace

//    ret : the return value for when yield() exits the function;

//          must match function return type (leave blank for no return type)

#define yield(x,ret)                            \

    {                                           \

        /* store the resume location */         \

        __asm {                                 \

            mov _myStaticMkr,offset label_##x   \

        }                                       \

                                                \

        /* return the supplied value */         \

        return ret;                             \

    }                                           \

    /* our offset in the function */            \

    label_##x:

//

// resumes function from the stored offset, or

// continues without notice if there's not one

// stored

//

// resume()

//   <void

#define resume()                        \

    /* our stored offset */             \

    static _myStaticMkr=;              \

                                        \

    /* test for no offset */            \

    if( _myStaticMkr )                  \

    {                                   \

        /* resume from offset */        \

        __asm                           \

        {                               \

            jmp _myStaticMkr            \

        }                               \

    }

// example demonstrating a function with an int return type

// using the yield() and resume() macros

//

// myFunc()

//   <void

int myFunc()

{

    resume();

    cout << "1\n";

    yield(,);

    cout << "2\n";

    yield(,);

    cout << "3\n";

    yield(,);

    cout << "4\n";

    return ;

}

// main function

//

// main()

//   <void

void main( void )

{

    cout << "Yield in C++\n";

    cout << "Chris Pergrossi\n\n";

    myFunc();

    do

    {

        cout << "main()\n";

        cout.flush();

    } while( myFunc() );

    cout.flush();

    getch();

}

/*

// example demonstrating a function with no return type

// using the yield() and resume() macros

//

// myFunc()

//   <void

void myFunc()

{

    resume();

    cout << "1\n";

    yield(1);

    cout << "2\n";

    yield(2);

    cout << "3\n";

    yield(3);

    cout << "4\n";

    return;

}

// main function

//

// main()

//   <void

void main( void )

{

    cout << "Yield in C++\n";

    cout << "Chris Pergrossi\n\n";

    myFunc();

    for( int k = 0; k < 4; k ++ )

    {

        cout << "main()\n";

        cout.flush();

        myFunc();

    }

    cout.flush();

    getch();

}

*/