错误的权限我有练习5-13 K & R的问题,练习的目标是制作一个与* nix命令相同的函数尾部,这里是我的功能:strcpy()错误:映射区域在地址
#include <stdio.h>
#include <string.h>
#include "tail.h"
int tail(int n)
{
char *saved_lines[n];
for (int i = 0; i < n; i++)
saved_lines[i] = "\0";
int line_state[n];
for (int j = 0; j < n; j++)
line_state[j] = 0;
int num_lines = 0, i = 0;
char line[MAXLINE];
saved_lines[n - 1] = "\0";
while (get_line(line, MAXLINE) > 0)
{
for (i = 0; i < n - 1; i++)
{
strcpy(saved_lines[i], saved_lines[i + 1]);
line_state[i] = line_state[i + 1];
}
strcpy(saved_lines[n - 1], line);
line_state[n - 1] = 1;
}
printf("last %d lines: \n", n);
for (i = 0; i < n; i++)
if (line_state[i] == 1)
printf("%d: %s\n", i, saved_lines[i]);
}
问题是,当我运行它,我得到一个Segmentation fault (core dumped)
错误,并通过Valgrind的运行它显示的错误来自调用strcpy
:
==25284== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==25284== Bad permissions for mapped region at address 0x108E64
...我不不明白为什么,起初strcpy
与01有问题个指针被初始化非,固定与
for(int i=0;i<n;i++)
saved_lines[i]="\0";
没有帮助...任何想法可能导致此?提前致谢!
编辑:开始 - >初始化
指针都被初始化为指向字符串文字。你需要一些实际的存储空间。 –
OT:“*启动*”--->“初始化” – alk
为char数组中的每个单词分配一些内存,它们指向字符串文字。字符文字作为二进制文件的一部分存储在“只读”位置。你应该知道'strcpy'修改了它的参数。这将帮助你,[关于字符串文字](https://stackoverflow.com/questions/2589949/string-literals-where-do-they-go),[SimilarQuestion](https://stackoverflow.com/questions/ 11379412/crash-when-handling-char-initd-with-string-literal-but-with-malloc) – WhiteSword