gdb学习5：打印函数堆栈和退出函数

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 代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

char *MyStrCopy1(const char *s1)
{
	if(NULL == s1)
	{
		return "string is NULL";
	}
	else
	{

		char *s2 = (char *)malloc(strlen(s1)+1);
		if(NULL == s2)
		{
			return "malloc error";
		}
		char *p = s2;
		while((*s2++ = *s1++));
		return p;
	}	
}

char *MyStrCopy2(const char *s1,char *s2)
{
	char *p = s2;
	while(*s2++ == *s1++);
	//while(*s2++ = *s1++);
	return p;
}

int main(int argv,char **argc)
{
	const char *str1 = NULL;
	const char *str2 = "string copying";
	char str3[strlen(str2)+1];
	//char str3[20];
	printf("%s\n",MyStrCopy1(str1));
	printf("%s\n",MyStrCopy1(str2));
	char *res = MyStrCopy2(str2,str3);
	printf("%s\n",res);
	return 0;
}

编译运行：

gyz@debian:~/mc$ gcc strcopy.c -o strcopy -g -Wall
gyz@debian:~/mc$ gdb strcopy 

 直接进入新内容。

(gdb) bt
#0  main (argv=1, argc=0x7fffffffe228) at strcopy.c:41
(gdb) s
MyStrCopy2 (s1=0x555555554990 "string copying", s2=0x7fffffffe0c0 "\001")
    at strcopy.c:27
27		char *p = s2;
(gdb) bt
#0  MyStrCopy2 (s1=0x555555554990 "string copying", s2=0x7fffffffe0c0 "\001")
    at strcopy.c:27
#1  0x00005555555548bc in main (argv=1, argc=0x7fffffffe228) at strcopy.c:41
(gdb) finish
Run till exit from #0  MyStrCopy2 (s1=0x555555554990 "string copying", 
    s2=0x7fffffffe0c0 "\001") at strcopy.c:27
0x00005555555548bc in main (argv=1, argc=0x7fffffffe228) at strcopy.c:41
41		char *res = MyStrCopy2(str2,str3);
Value returned is $1 = 0x7fffffffe0c0 "\001"
(gdb) n
42		printf("%s\n",res);
(gdb) 

解释：

1，bt（不知道这个是哪个单词的简写，知道的，请留言）可以打印函数堆栈，上面用s进入了函数MyStrCopy2()，可以看到bt打印的信息是层层递进的；

2，finish命令可以直接退出当前函数，不需要再用n一步一步的执行完再退出函数。