Question

我已经读过manual的strtok_r，并且相对确定可以正确使用它，但是每次都会出现段错误。

所以我决定编写一个快速测试程序，发现这也存在段错误：

//This define probably not necessary
//POSIX_C_SOURCE is defined as 200809L on my system
//It still doesn't work even with this define though..
#define _POSIX_SOURCE 

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

int main(void)
{
    char input[255];
    char* token;
    char** saveptr;

    memset(input, 0, sizeof(char) * 255);
    fgets(input, sizeof(input), stdin);
    token = strtok_r(input, ":", saveptr);
}

从valgrind追溯：

==15796== Command: ./a.out
==15796== 
==15796== Use of uninitialised value of size 8
==15796==    at 0x4EDABA4: strtok_r (strtok_r.c:73)
==15796==    by 0x10878B: main (in /home/pluh/a.out)
==15796== 
==15796== Invalid write of size 8
==15796==    at 0x4EDABA4: strtok_r (strtok_r.c:73)
==15796==    by 0x10878B: main (in /home/pluh/a.out)
==15796==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==15796== 
==15796== 
==15796== Process terminating with default action of signal 11 (SIGSEGV)

我只将“ test”放在标准输入中，所以我知道它没有溢出。我在这里做错什么了吗？这是我能想到的最简单的使用场景，但仍然无法解决。

Answer 1

尝试这种方式：

int main(void)
{
    char input[255];
    char* token;
    char* saveptr;

    fgets(input, sizeof(input), stdin);
    token = strtok_r(input, ":", &saveptr);

    printf("%s, %s\n",token,saveptr);
}

每当我调用strtok_r（）segfault时，即使在简单的情况下

1 个答案: