为什么我在这里收到“不允许在常量表达式中调用函数”错误消息？

Question

我试图使用C以面向对象的方式进行编码。我的目标是从基类“ Shape”派生“ Square”类。但是我收到一条错误消息“常量表达式中不允许函数调用”。为什么我会收到此消息以及如何解决此问题？

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//shape.h

//Some code
typedef struct ShapeType{
    int buffer_size;
    const char* (*name)(Shape*);
    int (*sides)(Shape*);
    void (*destroy)(Shape*);
} ShapeType;

ShapeType* ShapeType_create(
    int buffer_size,
    const char* (*name)(Shape*),
    int (*sides)(Shape*),
    void (*destroy)(Shape*)
);

//Some code

//square.c
typedef struct SquareData{
    int x;
    int y;
    int width;
    int height;
} SquareData;

//...

const char* square_name(Shape * self)
{
    return "Square";
}

int square_sides(Shape * self)
{
    return 4;
}

void* square_destroy(Shape * square)
{
    free(square);
}

static ShapeType* square_type = 
    ShapeType_create(
        sizeof(SquareData),
        &square_name, 
        &square_sides, 
        &square_destroy
    ); //error in this line

//...