file creation time system call in linux/gcc

Question

As I know, stat/fstat system call tell us only 3 times about a file

• Time of last access (st_atim field)
• Time of last modification (st_mtim field)
• Time of last status change (st_ctim)

and when I run stat filename command in bash, I can get creation time as Birth of the file. My question is, how can I get creation time in gcc by some system calls?

Answer 1

Use statx.

From man 2 statx:

SYNOPSIS #include <sys/types.h> #include <sys/stat.h> #include <unistd.h> #include <fcntl.h> /* Definition of AT_* constants */

   int statx(int dirfd, const char *pathname, int flags,
             unsigned int mask, struct statx *statxbuf);

DESCRIPTION This function returns information about a file, storing it in the buffer pointed to by statxbuf. The returned buffer is a structure of the fol‐ lowing type:

       struct statx {
           __u32 stx_mask;        /* Mask of bits indicating
                                     filled fields */
           __u32 stx_blksize;     /* Block size for filesystem I/O */
           __u64 stx_attributes;  /* Extra file attribute indicators */
           __u32 stx_nlink;       /* Number of hard links */
           __u32 stx_uid;         /* User ID of owner */
           __u32 stx_gid;         /* Group ID of owner */
           __u16 stx_mode;        /* File type and mode */
           __u64 stx_ino;         /* Inode number */
           __u64 stx_size;        /* Total size in bytes */
           __u64 stx_blocks;      /* Number of 512B blocks allocated */
           __u64 stx_attributes_mask;
                                  /* Mask to show what's supported
                                     in stx_attributes */

           /* The following fields are file timestamps */
           struct statx_timestamp stx_atime;  /* Last access */
           struct statx_timestamp stx_btime;  /* Creation */
           struct statx_timestamp stx_ctime;  /* Last status change */
           struct statx_timestamp stx_mtime;  /* Last modification */

That shows a field for a creation file stamp, appropriately named stx_btime (status extended birth time, I guess).

Note that for Darwin (and presumably any BSD), stat() contains a field struct timespec st_birthtimespec already, and there is no statx().