使用strtok_r时,我不应该释放char

Question

每次调用strtok_r()(从字符串中提取标记)后,我不应该释放s_ptr吗？

static void get_uevent_info(struct media_device_entry *md_ptr, char *dname)
{
    FILE *fd;
    char file[PATH_MAX], *name, *p;
    char s[1024];
    char *s_ptr;

    snprintf(file, PATH_MAX, "%s/%s/uevent", dname, md_ptr->node);
    fd = fopen(file, "r");
    if (!fd)
            return;
    while (fgets(s, sizeof(s), fd)) {
            p = strtok_r(s, "=", &s_ptr);
            if (!p)
                    continue;
            name = p;
            p = strtok_r(NULL, "\n", &s_ptr);
            if (!p)
                    continue;
            if (!strcmp(name, "MAJOR"))
                    md_ptr->major = atol(p);
            else if (!strcmp(name, "MINOR"))
                    md_ptr->minor = atol(p);
    }

    fclose(fd);
}

我从未使用过这个功能,所以也许我错了.

最好的祝福.

Answer 1

s_ptr不应该被释放,因为它没有被mallocor calloc或者分配realloc.手册页说,

The saveptr argument is a pointer to a char * variable that is used internally by strtok_r() in order to maintain context between successive calls that parse the same string.

也就是说,strtok_r不分配内存.所以只需将指针地址发送到char即.char **就足够了,返回后无需任何操作.即使char *没有初始化也没关系,但仍然初始化指针NULL是避免恶梦的好习惯.