如何在Objective-C中测试stdin函数？

#import <Foundation/Foundation.h>

void handleInput() {
    NSFileHandle *input = [NSFileHandle fileHandleWithStandardInput];
    NSData *inputData = [input availableData];
    NSString *inputString = [[NSString alloc] initWithData:inputData encoding:NSUTF8StringEncoding];
    
    // 在这里对输入进行处理
    
    // 输出结果
    NSFileHandle *output = [NSFileHandle fileHandleWithStandardOutput];
    [output writeData:[inputString dataUsingEncoding:NSUTF8StringEncoding]];
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        handleInput();
    }
    return 0;
}