Executing C functions from C++ file results in linker error: "conflicting declaration with 'C' linkage" and "previous declaration 'C++' linkage

Question

我正在尝试从 Arduino 框架中的 C++ 文件中执行 C 函数。我尝试运行、GuiLib_ShowScreen 的函数出现在 GuiLib.h 和 GuiLib.c 中，如下所示（文件很大，为了方便和相关性，我只包含了定义）：

extern void GuiLib_ShowScreen(
      const GuiConst_INT16U StructureNdx,
      GuiConst_INT16S CursorFieldToShow,
      GuiConst_INT8U ResetAutoRedraw)
  { ... }

以及我要从中包含的文件 GuiLib_ShowScreen:

#ifndef _DISPLAY_DRIVER_H_
#define _DISPLAY_DRIVER_H_

#include <TFT_eSPI.h>
#include <SPI.h>
#include <ac.h>
#include <stdio.h>
#include "gui/GuiLib.h"

#define USE_DMAA_TO_TFT

extern "C"
{
    void GuiLib_ShowScreen(const GuiConst_INT16U StructureNdx, GuiConst_INT16S CursorFieldToShow, GuiConst_INT8U ResetAutoRedraw);
}

class display_
{
public:
    TFT_eSPI tft;
    bool getStatus();
    void initPWM();
    void writePWM(int duty);
};

#endif

还有我的main.cpp：

#include "display_driver.h"

void TaskPushDMA(void *pvParameters)
{
  while (true)
  {
    GuiLib_ShowScreen(GuiStruct_main_0, GuiLib_NO_CURSOR, GuiLib_RESET_AUTO_REDRAW);
    vTaskDelay(1000);
  }
}

我的问题是在编译时出现链接器错误，如下所示：

In file included from src\main.cpp:6:0:
src/display_driver.h:14:129: error: conflicting declaration of 'void GuiLib_ShowScreen(short unsigned int, short int, unsigned char)' with 'C' linkage
     void GuiLib_ShowScreen(const GuiConst_INT16U StructureNdx, GuiConst_INT16S CursorFieldToShow, GuiConst_INT8U ResetAutoRedraw);
                                                                                                                                 ^
In file included from src/display_driver.h:8:0,
                 from src\main.cpp:6:
src/gui/GuiLib.h:1847:13: note: previous declaration with 'C++' linkage
 extern void GuiLib_ShowScreen(
             ^

从我得到的信息来看，它似乎暗示原始链接是 C++，考虑到定义在 C 文件中，这很奇怪。我已经阅读了 here 以及之前在这里打开的问题，但没有运气。我还尝试创建这样的条件：

#ifdef __cplusplus
extern "C" int foo(int, int); // C++ compiler sees this
#else
int foo(int, int);            // C compiler sees this
#endif

Answer 1

在尝试了评论中的建议后，这清除了错误。我在 extern "C" 之后将库包含在范围之外，并将 GuiLib_ShowScreen() 的参数更改为其本机类型，在库中定义为 #define GuiConst_INT16U unsigned short。在范围内放置 include 语句存在兼容性问题，因为我的原始错误指出 previous declaration with 'C++' linkage 很明显 include 语句被自动解释为 C++ header 而不是 C.


extern "C"
{
    void GuiLib_ShowScreen(unsigned short StructureNdx, signed short CursorFieldToShow, unsigned char ResetAutoRedraw);
}

#include "gui/GuiLib.h"

Executing C functions from C++ file results in linker error: "conflicting declaration with 'C' linkage" and "previous declaration 'C++' linkage

Executing C functions from C++ file results in linker error: "conflicting declaration with 'C' linkage" and "previous declaration 'C++' linkage

c++

linker

arduino

linker-errors