Ubuntu Manpage: gd_add, gd_madd — add a field to a Dirfile

Provided by: libgetdata-doc_0.10.0-3build2_all

NAME

       gd_add, gd_madd — add a field to a Dirfile

SYNOPSIS

       #include <getdata.h>

       int gd_add(DIRFILE *dirfile, const gd_entry_t *entry);

       int gd_madd(DIRFILE *dirfile, const gd_entry_t *entry, const char *parent);

DESCRIPTION

The gd_add() function adds the field described by entry to the dirfile specified by
dirfile. The gd_madd() function behaves similarly, but adds the field as a metafield
under the field indicated by the field code parent.

The form of entry is described in detail on the gd_entry(3) man page. All relevant
members of entry for the field type specified must be properly initialised. If entry
specifies a CONST or CARRAY field, the field's data will be set to zero. If entry
specifies a STRING field, the field data will be set to the empty string.

The only flags in the entry->flags member which are honoured are GD_EN_HIDDEN, which
should be set or cleared to set the hiddenness of the entry (see gd_hidden(3)), and
GD_EN_COMPSCAL, which indicates whether scalar parameters are initialised from the complex
valued or purely real member, which both are present (LINCOM, POLYNOM, RECIP).

A metafield may be added either by calling gd_madd() with entry->field containing only the
metafield's name, or else by calling gd_add() with the fully formed "<parent-field>/<meta-
field>" field code in entry->field. Regardless of which interface is used, when adding a
metafield the value of entry->fragment_index is ignored and GetData will add the new
metafield to the same format specification fragment in which the parent field is defined.
If the specified parent field name is an alias, the canonical name of the field will be
substituted.

Fields added with this interface may contain either literal parameters or parameters based
on scalar fields. If an element of the entry->scalar array defined for the specified
field type is non-NULL, this element will be used as the scalar field code, and the
corresponding numerical member will be ignored, and need not be initialised. Conversely,
if numerical parameters are intended, the corresponding entry->scalar elements should be
set to NULL. If using an element of a CARRAY field, entry->scalar_ind should also be set.

RETURN VALUE

On success, gd_add() and gd_madd() return zero. On error, a negative-valued error code
is returned. Possible error codes are:

GD_E_ACCMODE
The specified dirfile was opened read-only.

GD_E_ALLOC
The library was unable to allocate memory.

GD_E_BAD_CODE
The field name provided in entry->field contained invalid characters; or it or an
input field did not contain the affected fragment's prefix or suffix. Alternately,
the parent field code was not found, or was already a metafield.

GD_E_BAD_DIRFILE
The supplied dirfile was invalid.

GD_E_BAD_ENTRY
There was an error in the specification of the field described by entry, or the
caller attempted to add a field of type RAW as a metafield.

GD_E_BAD_INDEX
The entry->fragment_index parameter was out of range.

GD_E_BAD_TYPE
The entry->data_type parameter provided with a RAW entry, or the entry->const_type
parameter provided with a CONST or CARRAY entry, was invalid.

GD_E_DUPLICATE
The field name provided in entry->field duplicated that of an already existing
field.

GD_E_INTERNAL_ERROR
An internal error occurred in the library while trying to perform the task. This
indicates a bug in the library. Please report the incident to the GetData
developers.

GD_E_IO An I/O error occurred while creating an empty binary file to be associated with a
newly added RAW field.

GD_E_PROTECTED
The metadata of the fragment was protected from change. Or, the creation of a RAW
field was attempted and the data of the fragment was protected.

GD_E_UNKNOWN_ENCODING
The encoding scheme of the indicated format specification fragment is not known to
the library. As a result, the library was unable to create an empty binary file
to be associated with a newly added RAW field.

GD_E_UNSUPPORTED
The encoding scheme of the indicated format specification fragment does not
support creating an empty binary file to be associated with a newly added RAW
field.

The error code is also stored in the DIRFILE object and may be retrieved after this
function returns by calling gd_error(3). A descriptive error string for the error may be
obtained by calling gd_error_string(3).

HISTORY

       The functions dirfile_add() and dirfile_madd() appeared in GetData-0.4.0.

       In GetData-0.7.0, the functions were renamed to gd_add() and gd_madd().

       In GetData-0.8.0, gd_add() first allowed adding metafields by providing the full (slashed)
       field  name.  This was the first version supporting fragment affixes, and in this version,
       gd_add() would apply the destination fragment's affixes to the supplied entry->field name.
       In  GetData-0.8.1, this changed: gd_add() now assumes entry->field contains the full field
       name, including any necessary affixes.

       In GetData-0.10.0, the error return from these functions changed from -1  to  a  negative-
       valued error code.

       See gd_entry(3) for the history of the gd_entry_t structure.

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

HISTORY

SEE ALSO