stat

Syntax

#include <sys/stat.h>

int stat(const char *file, struct stat *sbuf);

Description

This function obtains the status of the file file and stores it in sbuf, which has this structure:

struct  stat {
        time_t   st_atime;     /* time of last modification */
        time_t   st_ctime;     /*            ''             */
        dev_t    st_dev;       /* The drive number (0 = a:) */
        gid_t    st_gid;       /* getgid() */
        ino_t    st_ino;       /* starting cluster or a unique identifier */
        mode_t   st_mode;      /* file mode - S_IF* and S_IRUSR/S_IWUSR */
        time_t   st_mtime;     /*            ''             */
        nlink_t  st_nlink;     /* 2 + number of subdirs, or 1 for files */
        off_t    st_size;      /* size of file in bytes */
        off_t    st_blksize;   /* the size of transfer buffer */
        uid_t    st_uid;       /* getuid() */
};

Return Value

Zero on success, nonzero on failure (and errno set).

Portability

not ANSI, POSIX

Example

struct stat s;
stat("data.txt", &s);
if (S_ISDIR(s.st_mode))
  printf("is directory\n");

Implementation Notes

Supplying a 100% Unix-compatible f?stat() functions under DOS is an implementation nightmare. The following notes describe some of the obscure points specific to their behavior in DJGPP.

1. The `drive' for character devices (like con, /dev/null and others is returned as -1. For drives networked by Novell Netware, it is returned as -2.

2. The starting cluster number of a file serves as its inode number. For files whose starting cluster number is inaccessible (empty files, files on networked drives, etc.) the st_inode field will be invented in a way which guarantees that no two different files will get the same inode number (thus it is unique). This invented inode will also be different from any real cluster number of any local file. However, only for local, non-empty files/directories the inode is guaranteed to be consistent between stat() and fstat() function calls.

3. The WRITE access mode bit is set only for the user (unless the file is read-only, hidden or system). EXECUTE bit is set for directories, files which can be executed from the DOS prompt (batch files, .com, .dll and .exe executables) or run by go32 extender.

4. Size of directories is reported as the number of its files (sans `.' and `..' entries) multiplied by 32 bytes (the size of directory entry). On FAT filesystems that support the LFN API (such as Windows 9x), the reported size of the directory accounts for additional space used to store the long filenames.

5. Time stamp for root directories is taken from the volume label entry, if that's available; otherwise, it is reported as 1-Jan-1980.

6. The variable section _djstat_flags controls what hard-to-get fields of struct stat are needed by the application.

7. stat() should not be used to get an up-to-date info about a file which is open and has been written to, because stat() will only return correct data after the file is closed. Use section fstat while the file is open.

8. The number of links st_nlink is always 1 for files other than directories. For directories, it is the number of subdirectories plus 2. This is so that programs written for Unix that depend on this to optimize recursive traversal of the directory tree, will still work.

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