On Fri, Nov 17, 2000 at 03:51:35PM +1100, Steve Smith wrote:
> "Steve" == Steve Smith <[EMAIL PROTECTED]> writes:
> > Hi, Could somebody tell me why the following testcase doesn't work?
>
> <snip>
>
> Nevermind, I got it from the archives eventually :
>
> seek $f, 0, 0;
^^^^
Had a look in Apache::File (below), and it sysopens, so you might want
to sysseek(...) instead.
That seek is flushing the filehandle for you though, here's without the
seek (on Linux, YMMV):
strace perl -we 'use Fcntl ; sysopen F, "foo", O_RDWR | O_CREAT or die $! ; print F
"hi1\n" ; sleep 5 ; print F "hi2\n" ; close F'
[snip]
open("foo", O_RDWR|O_CREAT|0x8000, 0666) = 3
fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|0x8000)
fstat(3, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0463, st_rdev=makedev(79, 18), ...}) =
0
mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x400180
00
_llseek(0x3, 0, 0, 0xbffff67c, 0x1) = 0
fstat(3, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0463, st_rdev=makedev(79, 18), ...}) =
0
fcntl(3, F_SETFD, FD_CLOEXEC) = 0
time([974438839]) = 974438839
SYS_175(0, 0xbffff8d0, 0xbffff850, 0x8, 0) = 0
SYS_174(0x11, 0, 0xbffff654, 0x8, 0x11) = 0
SYS_175(0x2, 0xbffff850, 0, 0x8, 0x2) = 0
nanosleep(0xbffff7bc, 0xbffff7bc, 0x401791b4, 0xbffff7bc, 0xbffff8d0) = 0
time([974438844]) = 974438844
write(3, "hi1\nhi2\n", 8) = 8
close(3) = 0
and here's with the seek():
strace perl -we 'use Fcntl ; sysopen F, "foo", O_RDWR | O_CREAT or die $! ; print F
"hi1\n" ; seek F, 0, 0 ; sleep 5 ; print F "hi2\n" ; close F'
open("foo", O_RDWR|O_CREAT|0x8000, 0666) = 3
fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|0x8000)
fstat(3, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0463, st_rdev=makedev(79, 18), ...}) = 0
mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000
_llseek(0x3, 0, 0, 0xbffff66c, 0x1) = 0
fstat(3, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0463, st_rdev=makedev(79, 18), ...}) = 0
fcntl(3, F_SETFD, FD_CLOEXEC) = 0
write(3, "hi1\n", 4) = 4
_llseek(0x3, 0, 0, 0xbffff788, 0) = 0
time([974438924]) = 974438924
SYS_175(0, 0xbffff8c0, 0xbffff840, 0x8, 0) = 0
SYS_174(0x11, 0, 0xbffff644, 0x8, 0x11) = 0
SYS_175(0x2, 0xbffff840, 0, 0x8, 0x2) = 0
nanosleep(0xbffff7ac, 0xbffff7ac, 0x401791b4, 0xbffff7ac, 0xbffff8c0) = 0
time([974438929]) = 974438929
write(3, "hi2\n", 4) = 4
close(3) = 0
Calling syswrite bypasses Perl's buffering, but doesn't address the seek
issue:
open("foo", O_RDWR|O_CREAT|0x8000, 0666) = 3
fcntl(3, F_GETFL) = 0x8002 (flags O_RDWR|0x8000)
fstat(3, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0463, st_rdev=makedev(79, 18), ...}) = 0
mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000
_llseek(0x3, 0, 0, 0xbffff66c, 0x1) = 0
fstat(3, {st_mode=S_IFCHR|S_ISUID|S_ISGID|0463, st_rdev=makedev(79, 18), ...}) = 0
fcntl(3, F_SETFD, FD_CLOEXEC) = 0
write(3, "hi1\n", 4) = 4
time([974439066]) = 974439066
SYS_175(0, 0xbffff8c0, 0xbffff840, 0x8, 0) = 0
SYS_174(0x11, 0, 0xbffff644, 0x8, 0x11) = 0
SYS_175(0x2, 0xbffff840, 0, 0x8, 0x2) = 0
nanosleep(0xbffff7ac, 0xbffff7ac, 0x401791b4, 0xbffff7ac, 0xbffff8c0) = 0
time([974439071]) = 974439071
write(3, "hi2\n", 4) = 4
close(3) = 0
- Barrie
sub tmpfile {
my $class = shift;
my $limit = 100;
my $r = Apache->request;
while($limit--) {
my $tmpfile = "$TMPDIR/${$}" . $TMPNAM++;
my $fh = $class->new;
sysopen($fh, $tmpfile, $Mode, $Perms);
$r->register_cleanup(sub { unlink $tmpfile }) if $r;
if($fh) {
return wantarray ? ($tmpfile,$fh) : $fh;
}
}
}
