unix - 文件创建/打开对 st_mtime 和 st_atime 的影响

Question

当我使用 O_CREAT 标志在 UNIX 中创建或打开文件时，st_mtime、st_ctime 和 st_atime文件发生变化。但是，当我使用 O_TRUNC 标志创建或打开文件时，只有 st_mtime 和 st_ctime 更改，而不是 st_atime .

根据我的理解，st_atime 在访问文件时会发生变化。当我们使用 O_TRUNcflags打开或创建文件时，我们是否没有访问该文件？

Answer 1

这个问题有点老了，但至少为后代提供了答案......

来自 stat(2) 手册页(在具有 Linux 2.6.32 内核的主机上):

The field st_atime is changed by file accesses, for example, by execve(2), mknod(2), pipe(2), utime(2) and read(2) (of more than zero bytes). Other routines, like mmap(2), may or may not update st_atime.

The field st_mtime is changed by file modifications, for example, by mknod(2), truncate(2), utime(2) and write(2) (of more than zero bytes). Moreover, st_mtime of a directory is changed by the creation or deletion of files in that directory. The st_mtime field is not changed for changes in owner, group, hard link count, or mode.

The field st_ctime is changed by writing or by setting inode information (i.e., owner, group, link count, mode, etc.).