你如何建立一个C程序，其中包括在Mac OS X的切入点？ [英] How do you build a C program that includes the entry point on Mac OS X?

问题描述

你如何建立一个C程序，其中包括在Mac OS X？

How do you build a C program that includes the entry point on Mac OS X?

我想建立：

start() {
    /* exit system call */
    asm("movl $1,%eax;"
        "xorl %ebx,%ebx;"
        "int  $0x80"
    );
}

但是当我运行：

gcc -nostdlib min.c

我总是得到：

ld: could not find entry point "start" (perhaps missing crt1.o)
collect2: ld returned 1 exit status

我刚才提出的另外一个尝试，看看它所做的是运行：

The one other attempt I made just to see what it was doing was run:

gcc -nostdlib -c min.c && otool -tV min.o

和输出是：

(__TEXT,__text) section
_start:
0000000000000000    pushq   %rbp
0000000000000001    movq    %rsp,%rbp
0000000000000004    leave
0000000000000005    ret

所以，开始功能前从何而来的下划线？我如何prevent这种情况发生？或者更简单地说：

So where did that underscore come from before the "start" function? How do I prevent that from happening? Or more simply:

你如何建立一个C程序，其中包括在Mac OS X？

How do you build a C program that includes the entry point on Mac OS X?

谢谢，
CrazyChenz

Thanks, CrazyChenz

推荐答案

gcc的-e选项定义入口点，当你想要的入口点比启动其他的东西。这样，您就可以创建mystart（）作为你的切入点。

The gcc -e option defines the entry point, when you want the entry point to be something other than start. This way you can create mystart() as you entry point.

gcc -e mystart mycode.c -o mycode

我不知道如何设置X code中的-e选项。

I do not know how to set the -e option in Xcode.

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