readdir 调用的段错误

Question

我正在尝试执行 readdir()：这是代码：

DIR *dp;
struct dirent *dirp;

if (dp = opendir("saves") == NULL) {
    my_printf("Cannot open saves directory.\n");
    return 84;
} else if ((dirp = readdir(dp)) == NULL) {
    printf("hello\n");
} else 
    while ((dirp = readdir(dp)) != NULL)
        printf("%s\n", dirp->d_name);

我在 while ((dirp = readdir(dp)) != NULL) 上遇到段错误，程序没有通过 else if 语句。

Valgrind 输出：

==4398== Invalid read of size 4
==4398==    at 0x4AB99C3: readdir (in /usr/lib/libc-2.33.so)
==4398==    by 0x10C047: save_map (save_button.c:23)
==4398==    by 0x10C0ED: save_button_event (save_button.c:36)
==4398==    by 0x10BBA7: check_close (window_process.c:52)
==4398==    by 0x10A44F: main (my_world.c:19)
==4398==  Address 0x4 is not stack'd, malloc'd or (recently) free'd

有什么想法吗？

Answer 1

if (dp = opendir("saves") == NULL)

你错过了你需要的作业周围的括号，因为 == 的优先级高于 =。

您已将比较结果分配给 dp，这肯定不是有效指针。

你需要：

if ((dp = opendir("saves")) == NULL)

readdir 调用的段错误

segfault on readdir call

c

valgrind

coredump

readdir