lfc_perl(3)

1lfc_perl(3)            Perl Programmers Reference Guide            lfc_perl(3)
2
3
4

NAME

6       lfc - Perl interface to the LFC
7

SYNOPSIS

9       use lfc;
10       printf "CNS_LIST_BEGIN is %d\n", $lfc::CNS_LIST_BEGIN;
11

DESCRIPTION

13       The lfc module permits you to access the LFC client interface from perl
14       programs. The lfc module is a swig wrapping of the  standard  C  inter‐
15       face.   For  detailed  descriptions of each function see the individual
16       man page of each function.
17
18       There follows a series of examples of how to use selected functions and
19       how  to retrieve the information returned by them: Examples are finding
20       the GUID of an existing entry, listing the replicas of a given GUID and
21       setting and retrieving the comment associated with an entry.
22

EXAMPLE

24       #!/usr/bin/perl -w
25       use strict;
26       use lfc;
27
28       # stat an existing entry in the LFC and print the GUID
29       my ($name,$stat,$guid,$res);
30       $name = "/grid/dteam/my.test";
31
32       $stat = lfcc::new_lfc_filestatg();
33       $res = lfc::lfc_statg($name,undef,$stat);
34
35       if ($res == 0) {
36         $guid = lfcc::lfc_filestatg_guid_get($stat);
37         print "The GUID for $name is $guid\n";
38       } else {
39         my $err_num = $lfc::serrno;
40         my $err_string = lfc::sstrerror($err_num);
41         print "There was an error while looking for $name: Error $err_num ($err_string)\n";
42         exit(1);
43       }
44       lfcc::delete_lfc_filestatg($stat);
45

EXAMPLE

47       #!/usr/bin/perl -w
48       use strict;
49       use lfc;
50
51       # list the replicas of a given entry, starting from the GUID
52       my ($guid,$listp,$flag,$num_replicas);
53       $guid = "6a3164e0-a4d7-4abe-9f76-e3b8882735d1";
54
55       $listp = lfcc::new_lfc_list();
56       $flag =  $lfc::CNS_LIST_BEGIN;
57
58       print "Listing replicas for GUID $guid:\n";
59
60       $num_replicas=0;
61
62       while(1) {
63         my $res = lfc::lfc_listreplica(undef,$guid,$flag,$listp);
64         $flag = $lfc::CNS_LIST_CONTINUE;
65
66         if (!defined $res) {
67           last;
68         } else {
69           my $rep_name = lfcc::lfc_filereplica_sfn_get($res);
70           print "Replica: $rep_name\n";
71           $num_replicas++;
72         }
73       }
74       lfc::lfc_listreplica(undef,$guid,$lfc::CNS_LIST_END,$listp);
75       lfcc::delete_lfc_list($listp);
76
77       print "Found $num_replicas replica(s)\n";
78

EXAMPLE

80       #!/usr/bin/perl -w
81       use strict;
82       use lfc;
83
84       # setting and retrieving a comment on a file
85       my ($file,$res,$bufspec,$buffer,$comment);
86       $file = "/grid/dteam/my.test";
87
88       $comment = "MyComment";
89       $res = lfc::lfc_setcomment($file,$comment);
90
91       if ($res != 0) {
92         my $err_num = $lfc::serrno;
93         my $err_string = lfc::sstrerror($err_num);
94         print "Problem while setting comment for $file: Error $err_num ($err_string)\n";
95         exit(1);
96       }
97
98       $bufspec =  "x".($lfc::CA_MAXCOMMENTLEN+1);
99       $buffer = pack($bufspec);
100       $res = lfc::lfc_getcomment($file,$buffer);
101
102       if ($res != 0) {
103         my $err_num = $lfc::serrno;
104         my $err_string = lfc::sstrerror($err_num);
105         print "Problem while reading the comment for $file: Error $err_num ($err_string)\n";
106         exit(1);
107       }
108
109       $comment = unpack("Z*", $buffer);
110       print "Read back comment $comment\n";
111

NOTES

113       The   current   interface   to  the  lfc_getcomment(3),  lfc_getcwd(3),
114       lfc_readlink(3), lfc_seterrbuf(3) requires the passing  of  a  suitably
115       allocated buffer (in a similar way to the C functions). However this is
116       rather non standard in PERL. A future version of lfc perl interface may
117       do  away  with  the  need  to  setup  the buffer before the call and to
118       explicitly unpack the result afterwards.
119