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In comp.lang.perl.misc, 
    pvr@korfu.igd.fhg.de (Reiners Dirk) writes:
:Can I emulate/call the normal C open function in/from perl.
:I want to translate the following code to perl:
:
:st=open("foo",O_CREAT|O_EXCL,0777)
:
:for writing a lockfile function (some machines here don't support flock :-(
:
:I have already a solution like
:
:syscall(&SYS_open, "foo", O_CREAT|O_EXCL, 0777);
:
:but there seems to be no such function in sys/syscall.ph.
:I don't know if this is normal.
:(e.g.:
:IRIX  5.3	no SYS_open in syscall.ph
:SunOS 4.1.3     no syscall.ph at all
:)
:
:And I want the solution to work on both platform :-)
:Does anyone have an idea ?

I agree that this is not the best situation, but I *KNOW* that 
SunOS has a <syscall.h>, and wonder whether Irix does.  Check
with igrep:

    $ igrep open /usr/include/syscall.h

Meanwhile, we're thinking about a better solution.  Seems stoopid
to have to write a dot-xs module to do this.  It would be trivial 
though.

Meanwhile, here's igrep...

--tom


    #!/usr/local/bin/perl
    # igrep - tchrist@perl.com
    die "usage: $0 [-I path] pattern file ...\n" unless @ARGV > 1;
    @ipath = ( '.', '/usr/include', '/sys/h');
    while ($ARGV[0] =~ /^-I(.*)/) {
	shift;
	push(@ipath, $1 || shift);
    } 
    $pattern = shift;
    eval { /$pattern/ };  # test her
    die "$0: $@" if $@ =~ s/ at \(eval\).*//;
    for (@ARGV) { &process($_); } 
    exit (!$ok);
    sub process {
	local($fname) = @_;
	local(*FH);
	return if $seen{$fname};
	unless ($fname =~ m#^/# ? open(FH, $fname) : &iopen(FH, $fname)) {
	    warn "can't open $fname: $! called from "
		    . join(" from ", reverse @in) . "\n";
	    $seen{$fname}++; # sigh
	    return;
	}
	push(@in, $fname);
	unless($seen{$fname}++) {
	    while (<FH>) {
		#print "$fname: $.: $_" if /$pattern/o;
		print join(" from ", reverse @in), ": $.: $_"
		    if /$pattern/o;
		$ok++;
		next unless /^\s*#\s*include\s*(["<])([^">]+)\1/; 
		&process($2);
	    } 
	}
	pop @in;
	close(FH);
    } 

    sub iopen {
	local($fh, $path) = @_;
	local($mypath) = $in[$#in]; # cpp extra inc path
	$mypath = '' unless $mypath =~ s#/[^/]*$##;
	for $dir ($mypath, @ipath) {
	    next if $dir eq '';
	    next unless open ($fh, "$dir/$path");
	    $_[1] = "$dir/$path"; # clobber caller ref for better msgs
	    return 1;
	} 
	return 0;
    } 
-- 
Tom Christiansen      Perl Consultant, Gamer, Hiker      tchrist@mox.perl.com

Yield to Temptation ... it may not pass your way again.
                --Lazarus Long, "Time Enough for Love"