Objective-c 中的外部 C 函数

发布于 2024-07-24 23:11:09 字数 284 浏览 8 评论 0原文

我开发 iPhone 应用程序，更新到 sdk 3.0 后，链接时出现 CFWriteStreamCreateWithFTPURL 错误。这是我调用来获取错误的代码。

streamInfo.writeStream = CFWriteStreamCreateWithFTPURL(NULL, urlRefWrite);

我有一个想法，可以使用 extern "C" 来解决它，但是在谷歌搜索之后，我还没有找到解决我的问题的方法。有任何想法吗？

提前致谢

原文

i develop iPhone apps, and after updating to sdk 3.0, I get an error on CFWriteStreamCreateWithFTPURL while linking. This is the code I call to get the error.

streamInfo.writeStream = CFWriteStreamCreateWithFTPURL(NULL, urlRefWrite);

I have an idea that it can be solved using extern "C", but after having googled it, I have not found the solution to my problem. Any ideas?

Thanks in advance

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半步萧音过轻尘 2024-07-31 23:11:09

extern "C" 可能可以解决问题。我可以通过在实现和头文件声明周围执行类似的操作来编译和链接 C 函数。这是一个简单的例子：



#if __cplusplus
extern "C" {
#endif

/// converts a degree value to radians
double DegreesToRadians(double degrees);

/// converts radian value to degrees
double RadiansToDegrees(double radians);


#if __cplusplus
}   // Extern C
#endif

实现文件：


#import "Math.h"

#if __cplusplus
extern "C" {
#endif


double DegreesToRadians(double degrees) {return degrees * M_PI / 180;};
double RadiansToDegrees(double radians) {return radians * 180/M_PI;};


#if __cplusplus
} //Extern C
#endif

extern "C" may do the trick. I'm able to get C functions to compile and link by doing something like this both around the implementation and header file declaration. Here's a simple example:



#if __cplusplus
extern "C" {
#endif

/// converts a degree value to radians
double DegreesToRadians(double degrees);

/// converts radian value to degrees
double RadiansToDegrees(double radians);


#if __cplusplus
}   // Extern C
#endif

Implementation file:


#import "Math.h"

#if __cplusplus
extern "C" {
#endif


double DegreesToRadians(double degrees) {return degrees * M_PI / 180;};
double RadiansToDegrees(double radians) {return radians * 180/M_PI;};


#if __cplusplus
} //Extern C
#endif

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