Question

我试图在终端中使用gcc运行在Xcode中编写的多个HelloWorld文件。为了简明起见，这是来自 TutorialsPoint 的一个示例，位于名为myStandaloneHelloWorld.m的独立文件中：

#import <Foundation/Foundation.h>

@interface SampleClass:NSObject
- (void)sampleMethod;
@end

@implementation SampleClass

- (void)sampleMethod{
    NSLog(@"Hello, World! \n");
}

@end

int main()
{
    /* my first program in Objective-C */
    SampleClass *sampleClass = [[SampleClass alloc]init];
    [sampleClass sampleMethod];
    return 0;
}

在Xcode中编译但在终端中运行gcc myStandaloneHelloWorld.m时会产生以下错误列表：

Undefined symbols for architecture x86_64:
  "_NSLog", referenced from:
      -[SampleClass sampleMethod] in myStandaloneHelloWorld-0af75e.o
  "_OBJC_CLASS_$_NSObject", referenced from:
      _OBJC_CLASS_$_SampleClass in myStandaloneHelloWorld-0af75e.o
  "_OBJC_METACLASS_$_NSObject", referenced from:
      _OBJC_METACLASS_$_SampleClass in myStandaloneHelloWorld-0af75e.o
  "___CFConstantStringClassReference", referenced from:
      CFString in myStandaloneHelloWorld-0af75e.o
  "__objc_empty_cache", referenced from:
      _OBJC_METACLASS_$_SampleClass in myStandaloneHelloWorld-0af75e.o
      _OBJC_CLASS_$_SampleClass in myStandaloneHelloWorld-0af75e.o
  "_objc_msgSend", referenced from:
      _main in myStandaloneHelloWorld-0af75e.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

我知道还有其他框架和语法（例如在Xcode中运行的语法非常不同的Xcode命令行工具），但这种语法在终端中运行有什么问题？

Answer 1

您的程序依赖于Foundation框架。就像您必须告诉编译器（或链接器）有关您的程序所需的库一样，您必须告诉它有关框架的信息。

使用：

gcc myStandaloneHelloWorld.m -framework Foundation

如何在Xcode之外编译和运行objective-c文件？

1 个答案: