通过 function 传递结构指针然后访问结构数据

Question

I'm working on a function that works as part of a larger program. My C pointer skills are a bit rusty and so I need some help here.

Notice: I've omitted a lot of the program because it is irrelevant and works correctly, all you need to know is that I import a header file that declares the struct ImportedStruct , also, I cannot change the function header, so I need to pass the ImportedStruct as a pointer and the function as a pointer.

I get the following error message in VS code: pointer to incomplete class type is not allowed .

Any ideas?

#include "name.h"
long int *functionName(struct ImportedStruct *structName, int *irrelevant){
    int width = structName->width;
    int height = structName->height;

    // Remaining function ...
}

Header file:

struct ImportedStruct 
{ 
  int width, height;
};

Answer 1

I just compiled the code you provide

struct ImportedStruct 
{ 
  int width, height;
};

long int *functionName(struct ImportedStruct *structName, int *irrelevant){
    int width = structName->width;
    int height = structName->height;

    // Remaining function ...
    return (long int *)(width + height);
}

and it compiled successfully.

Make sure struct definition is included. Also, you can put

struct ImportedStruct 
{ 
  int width, height;
};

right before your function definition. If compiler does not give you multiple definition error, then struct definition is not included by headers.