This function prepares for an Extended Service Request.
Extended Services is family of various Z39.50 facilities, such
as Record Update, Item Order, Database administration etc.
Note:
Many Z39.50 Servers do not support Extended Services.
The yaz_es() creates an Extended Service Request
packages and puts it into a queue of operations.
Use yaz_wait() to send the request(s) to the server.
After completion of yaz_wait() the result of
the Extended Service operation should be expected with
a call to yaz_es_result().
A string which represents the type of the Extended Service:
itemorder (Item Order),
create (Create Database),
drop (Drop Database),
commit (Commit Operation),
update (Update Record),
xmlupdate (XML Update).
Each type is specified in the following section.
args
An array with extended service options plus
package specific options. The options are identical to
those offered in the C API of ZOOM C. Refer to
the ZOOM » Extended Services.