[comp.lang.perl] perl under SR10.1; trouble with "stat"

jnp@mjolner.tele.nokia.fi (J|rgen N|rgaard) (02/02/90)

On installing perl (latest release with patches) I had some worries
because the tests some times would fail on "op.stat". Deciding to
investigate on little on this I wrote the attached small c-piece.

So my question os two-fold:
      i) how is "stat" supposed to work under BSD4.3 ?
         i.e. should "mtime" and "ctime" be equal upon
         creating of a fresh file ?
     ii) If so, why is Apollo different ? And what to do about it ?
	 Is this fixed in SR10.2 ?

(Machine: Apollo DN3500, SR10.1, BSD4.3, native cc)

Any help appreciated.

/j|rgen n|rgaard


File "stat.c":
    #include <stdio.h>
    #include <sys/errno.h>
    #include <sys/file.h>
    #include <sys/types.h>
    #include <sys/stat.h>

    main(argc,argv)
    int argc;
    char *argv[];
    {     
      int fd;
      struct stat buf;

      (void) unlink("./foo.tmp");
      fd = open("./foo.tmp", O_CREAT | O_RDWR, 00200);
      printf("fd: %d, %d.\n", fd, errno);

      printf("stat: %d.\n", stat("./foo.tmp", &buf));
      printf("stat.st_mtime: %u, stat.st_ctime: %u.\n", buf.st_mtime, buf.st_ctime); 
      printf("stat: %d.\n", stat("./foo.tmp", &buf));
      printf("stat.st_mtime: %u, stat.st_ctime: %u.\n", buf.st_mtime, buf.st_ctime); 
      (void) unlink("foo.tmp");
    };

Result:
    mjolner :~/src/c/test (1) a.out
    fd: 3, 2.
    stat: 0.
    stat.st_mtime: 633958917, stat.st_ctime: 633958918.
    stat: 0.
    stat.st_mtime: 633958917, stat.st_ctime: 633958918.
    mjolner :~/src/c/test (2) !!
    a.out
    fd: 3, 2.
    stat: 0.
    stat.st_mtime: 633958924, stat.st_ctime: 633958924.
    stat: 0.
    stat.st_mtime: 633958924, stat.st_ctime: 633958924.
    mjolner :~/src/c/test (3) !!
    a.out
    fd: 3, 2.
    stat: 0.
    stat.st_mtime: 633958926, stat.st_ctime: 633958927.
    stat: 0.
    stat.st_mtime: 633958926, stat.st_ctime: 633958927.
    mjolner :~/src/c/test (4) !!
    a.out
    fd: 3, 2.
    stat: 0.
    stat.st_mtime: 633958929, stat.st_ctime: 633958929.
    stat: 0.
    stat.st_mtime: 633958929, stat.st_ctime: 633958929.
    mjolner :~/src/c/test (5) 


--
------------------------ ORIGIN  '~jnp/stdDisclaimers' ------------------------
| Regards, J|rgen N|rgaard ('|' is '\o{}' in \LaTeX{})                        |
|    e-mail: jnp@tele.nokia.fi | telephone: <..>-358-0-511-5671               |
--    mail: Nokia Telecommunications, PL 33, SF-02601 Espoo, Suomi Finland   --

carlton@apollo.HP.COM (Carlton B. Hommel) (02/04/90)

A summary of the problem:  The "ctime" and "mtime" reported
by stat(2) are different for a newly created file, when you
would expect them to be the same.  Ie, 
    stat.st_mtime: 634104703 stat.st_ctime: 634104704

I'm pretty sure that it is a byproduct of our implementation
of the open(2) system call, but I'm just a perl fanatic, and
not a systems hacker.

This problem still exists at our hot-off-the-presses sr10.2+
baselevel, so I've posted it as a bug.  If you want a formal
answer, then please submit an APR.  (See "man mkapr" for help.)

Carl Hommel
carlton@apollo.hp.com
"I could write a perl script to do that for you..."