Open Client Client-Library/C Reference Manual

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Open Client Client-Library/C Reference Manual

Chapter 2 Topics

Client-Library and SQL Structures

Exposed and hidden structures

Client-Library structures fall into two categories: a is a structure whose internals are not documented, and an is a structure whose internals are documented.

Exposed structures

Exposed structures provide a way for Client-Library to exchange information with an application. Typically, applications set fields in an exposed structure before passing the structure as a parameter to a Client-Library routine, and retrieve the values of fields in an exposed structure after calling a Client-Library routine.

Exposed structures include:

CS_BROWSEDESC, the browse descriptor structure
CS_CLIENTMSG, the Client-Library message structure
CS_DATAFMT, the data format structure
CS_IODESC, the I/O descriptor structure
CS_SERVERMSG, the server message structure
SQLCA, the SQL Communications Area structure
SQLCODE, the SQL Code structure
SQLSTATE, the SQL State structure

These exposed structures are documented in the following sections.

Hidden structures

Client-Library uses hidden structures to manage a variety of internal tasks.

A Client-Library application cannot directly access hidden structure internals. Instead, the application must call Client-Library routines to allocate, manipulate, and deallocate hidden structures.

Hidden structures include:

CS_BLKDESC, a control structure used by Client-Library's and Server-Library's bulk copy routines.
CS_CAP_TYPE, which is used to store capability information.
CS_COMMAND, which is used to send commands and process results.
CS_CONNECTION, which defines an individual client/server connection.
CS_CONTEXT, which defines a Client-Library programming context.
CS_LOCALE, which is used to store localization information.
CS_LOGINFO, the server login information structure. This structure, which is associated with a CS_CONNECTION, contains server login information such as user name and password.

The following table lists the routines and macros that allocate, manipulate, and deallocate hidden structures:.

Routines that manipulate hidden structures
Structure	Routines	For more information
CS_BLKDESC	blk_alloc, blk_drop	Open Client and Open Server Common Libraries Reference Manual.
CS_CAP_TYPE	CS_CLR_CAPMASK, CS_SET_CAPMASK, CS_TST_CAPMASK	"Setting and retrieving multiple capabilities".
CS_COMMAND	ct_cmd_alloc, ct_cmd_props, ct_cmd_drop	Reference pages for these routines.
CS_CONNECTION	ct_con_alloc, ct_con_props, ct_con_drop	Reference pages for these routines.
CS_CONTEXT	cs_ctx_alloc, ct_config, cs_config, cs_ctx_drop	Reference pages for these routines. CS-Library routines are documented in the Open Client and Open Server Common Libraries Reference Manual.
CS_LOCALE	cs_loc_alloc, cs_locale, cs_loc_drop	"International Support". Open Client and Open Server Common Libraries Reference Manual.
CS_LOGINFO	ct_getloginfo, ct_setloginfo	Reference pages for these routines.


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