#
# Copyright (c) 2002, 2003, Oracle and/or its affiliates. All rights reserved.
#

#
# Sun::Solaris::Exacct::File documentation.
# 

=head1 NAME

Sun::Solaris::Exacct::File - exacct file manipulation

=head1 SYNOPSIS

 use Sun::Solaris::Exacct::File qw(:ALL);
 my $ea_file = Sun::Solaris::Exacct::File->new($myfile, &O_RDONLY);
 my $ea_obj = $ea_file->get();

This module provides access to the C<libexacct(3LIB)> functions that
manipulate accounting files. The interface is object-oriented and allows the
creation and reading of libexacct files. The C library calls wrapped by this
module are C<ea_open(3EAXACCT)>, C<ea_close(3EAXACCT)>,
C<ea_next_object(3EAXACCT)>, C<ea_previous_object(3EAXACCT)>,
C<ea_write_object(3EAXACCT)>, C<ea_get_object(3EAXACCT)>,
C<ea_get_creator(3EAXACCT)>, and C<ea_get_hostname(3EAXACCT)>. The file read
and write methods all operate on C<Sun::Solaris::Exacct::Object> objects and
perform all the necessary memory management, packing, unpacking, and structure
conversions that are required.

=head2 Constants

C<EO_HEAD>, C<EO_TAIL>, C<EO_NO_VALID_HDR>, C<EO_POSN_MSK>, and
C<EO_VALIDATE_MSK>. Other constants needed by the C<new()> method below are in
the standard Perl C<Fcntl> module.

=head2 Functions

None.

=head2 Class methods

B<C<< new($name, $oflags, creator => $creator,
    aflags => $aflags, mode => $mode) >>>

This method opens a libexacct file as specified by the mandatory parameters
C<$name> and C<$oflags>, and returns a C<Sun::Solaris::Exacct::File> object,
or C<undef> if an error occurs. The parameters C<$creator>, C<$aflags>, and
C<$mode> are optional and are passed as C<(name => value)> pairs. The only
valid values for C<$oflags> are the combinations of C<O_RDONLY>, C<O_WRONLY>,
C<O_RDWR>, and C<O_CREAT> described below.

The C<$creator> parameter is a string describing the creator of the file. If
it is required (for instance, when writing to a file) but absent, it is set to
the string representation of the caller's UID. The C<$aflags> parameter
describes the required positioning in the file for C<O_RDONLY> access: either
C<EO_HEAD> or C<EO_TAIL> are allowed. If absent, C<EO_HEAD> is assumed. The
C<$mode> parameter is the file creation mode and is ignored unless C<O_CREAT>
is specified in C<$oflags>. If C<$mode> is unspecified, the file creation mode
is set to C<0666> (octal). If an error occurs, it can be retrieved with the
C<Sun::Solaris::Exacct::ea_error()> function.
(See C<Sun::Solaris::Exacct(3)>).

B<C< $oflags             $aflags               Action>>

 O_RDONLY            Absent or EO_HEAD     Open for reading
                                           at the start  of
                                           the file.

 O_RDONLY            EO_TAIL               Open for reading
                                           at the end of the
                                           file.

 O_WRONLY            Ignored               File must exist,
                                           open for writing
                                           at the end of the
                                           file.

 O_WRONLY | O_CREAT  Ignored               Create file if it
                                           does not exist,
                                           otherwise truncate
                                           and open for writing.

 O_RDWR              Ignored               File must  exist,
                                           open for
                                           reading/writing,
                                           positioned at the
                                           end of the file.

 O_RDWR | O_CREAT    Ignored               Create file if it
                                           does not exist,
                                           otherwise truncate
                                           and open for
                                           reading/writing.

=head2 Object methods

B<Note:> Closing a C<Sun::Solaris::Exacct::File>

There is no explicit C<close()> method for a C<Sun::Solaris::Exacct::File>.
The file is closed when the file handle object is undefined or reassigned.

B<C<creator()>>

This method returns a string containing the creator of the file or C<undef> if
the file does not contain the information.

B<C<hostname()>>

This method returns a string containing the hostname on which the file was
created, or C<undef> if the file does not contain the information.

B<C<next()>>

This method reads the header information of the next record in the file. In a
scalar context the value of the type field is returned as a dual-typed scalar
that will be one of C<EO_ITEM>, C<EO_GROUP>, or C<EO_NONE>. In a list context
it returns a two-element list containing the values of the type and catalog
fields. The type element is a dual-typed scalar. The catalog element is
blessed into the C<Sun::Solaris::Exacct::Catalog> class. If an error occurs,
C<undef> or C<(undef, undef)> is returned depending upon context. The status
can be accessed with the C<Sun::Solaris::Exacct::ea_error()> function. (See
C<Sun::Solaris::Exacct(3)>).

B<C<previous()>>

This method reads the header information of the previous record in the file.
In a scalar context it returns the type field. In a list context it returns
the two element list containing the values of the type and catalog fields, in
the same manner as the C<next()> method. Error are also returned in the same
manner as the C<next()> method.

B<C<get()>>

This method reads in the libexacct record at the current position in the file
and returns a C<Sun::Solaris::Exacct::Object> containing the unpacked data
from the file. This object can then be further manipulated using its methods.
In case of error C<undef> is returned and the error status is made available
with the C<Sun::Solaris::Exacct::ea_error()> function. After this operation,
the position in the file is set to the start of the next record in the file.

B<C<write(@ea_obj)>>

This method converts the passed list of C<Sun::Solaris::Exacct::Object>s into
libexacct file format and appends them to the libexacct file, which must be
open for writing. This method returns C<true> if successful and C<false>
otherwise. On failure the error can be examined with the
C<Sun::Solaris::Exacct::ea_error()> function.

=head2 Exports

By default nothing is exported from this module. The following tags can be
used to selectively import constants defined in this module:

 :CONSTANTS   EO_HEAD, EO_TAIL,  EO_NO_VALID_HDR,  EO_POSN_MSK,  and
              EO_VALIDATE_MSK

 :ALL         :CONSTANTS, Fcntl(:DEFAULT).

=head1 ATTRIBUTES

See C<attributes(5)> for descriptions of the following attributes:

  ___________________________________________________________
 |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
 |_____________________________|_____________________________|
 | Availability                | SUNWpl5u                    |
 |_____________________________|_____________________________|
 | Interface Stability         | CPAN (http://www.cpan.org)  |
 |_____________________________|_____________________________|

=head1 SEE ALSO

C<ea_close(3EXACCT)>, C<ea_get_creator(3EXACCT)>, C<ea_get_hostname(3EXACCT)>,
C<ea_get_object(3EXACCT)>, C<ea_next_object(3EXACCT)>, C<ea_open(3EXACCT)>,
C<ea_previous_object(3EXACCT)>, C<ea_write_object(3EXACCT)>,
C<Sun::Solaris::Exacct(3)>, C<Sun::Solaris::Exacct::Catalog(3)>,
C<Sun::Solaris::Exacct::Object(3)>, C<Sun::Solaris::Exacct::Object::Group(3)>,
C<Sun::Solaris::Exacct::Object::Item(3)>, C<libexacct(3LIB)>, C<attributes(5)>