cdds_mod - initialize DDS dictionary for modification of binary data.

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SYNOPSIS

const char * cdds_mod(alias, value, title, history);

const char *alias
const char *value
const char *title
const char *history

[ Description | Input | Output | Examples ]

DESCRIPTION

Applications may update the dictionary contents by appending (print) definitions. The cdds_open function may also update the dictionary. Changes are frozen, after the binary data is opened.

Note: This function changes the scan and print dictionary selection. It implicitly calls cdds_dict to select new names and modes. After a dictionary is initialized, it may be switched between scan and print modes by calling cdds_dict.

INPUT

Mutiple definition names, delimited by white space, may be specified by alias. If specified, the "par:" dictionary is searched. If a definition is found, its value is taken as a dictionary name. This feature is disabled, if a null alias is specified (i.e. NULL, zero length string, or a string that only contains white space).

A default dictionary name may be specified by value. The default is used if the "par:" dictionary does not define alias, or a null alias is specified. If there is no appropriate default, then a null value should be specified. A temporary dictionary is created, if an explicit name is not available.

The value default is ignored in special cases. These exceptions make it convenient to use DDS programs with standard formats and non-DDS applications. cdds_mod ignores the default, if value is "stdin:" or "stdout:".

The title argument should provide a brief (one line) description of the application program. The title is accumulated in the history, along with other definitions (it is not used if a new dictionary is being created). For example:

...previous history
DDS_SENTRY= $Revision: 57 $ $Date: 2009-02-11 17:09:37 -0600 (Wed, 11 Feb 2009) $
********************************************
******************* TITLE ******************
********************************************
cmd_title=  "bridge, convert seismic data"
cmd_name= /dist/Linux/2.6/mbs/prod/i686/bridge
cmd_rev= 1.10
cmd_user= DoeJohnw
cmd_date= Mon Oct 23 10:24:20 2006
cmd_host= machine2
cmd_cwd= /data/line2
cmd_pid= 6753
alias:sep_in= in
$size=
$origin=
$delta=
$units=
dds_history{= par:
...contents of par: dictionary
dds_history}= par:
    

OUTPUT

The dictionary is closed and the memory is freed when the associated binary file is closed. However, if the memory for the output dictionary names must be freed then use cdds_free instead of any other system 'free' routine.

EXAMPLES

const char *mod_dict;

/* create/update velocity model dictionary */
mod_dict = cdds_mod("vel", "model", "model update", in_dict);
          

SEE ALSO

cdds_dict Select DDS dictionary and mode
    

AUTHOR