dbretdata

Returns a pointer to a returned parameter value generated by a stored procedure or a remote stored procedure.

Syntax

LPCBYTE dbretdata (
PDBPROCESS dbproc,
INT retnum );

Arguments

dbproc

Is the DBPROCESS structure that is the handle for a particular workstation/ Microsoft® SQL Server™ process. It contains all the information that DB-Library uses to manage communications and data between the workstation and SQL Server.

retnum

Is the number of the returned value of interest. The first return value is number 1. Values are returned in the same order as the parameters were originally specified in the stored procedure’s CREATE PROCEDURE statement. (Note that the order is not necessarily the same as that specified in the remote stored procedure.) When specifying retnum, nonreturn parameters are not counted. For example, if the second parameter in a stored procedure is the only return parameter, its retnum is 1, not 2.

Returns

A pointer to the specified return value. If retnum is out of range, dbretdata returns NULL. To determine whether the data really has a null value (and retnum is not merely out of range), check for a return value of 0 from dbretlen.

Remarks

The server returns stored procedure information (including any return status and parameter values) immediately after returning all normal results for that stored procedure. Process the normal results, and then call dbretdata after dbresults returns NO_MORE_RPC_RESULTS (for all stored procedures in a batch except the last one) or NO_MORE_RESULTS (for a single stored procedure, or for the last stored procedure in a batch).

Stored procedures can return values for specified parameters. If the value of one of these parameters is changed within a stored procedure, the new value is returned to the program that called the procedure. This action parallels the pass-by-reference facility available in some programming languages.

To function as a return parameter, a parameter must be declared as such:

• When a stored procedure is created with CREATE PROCEDURE, the parameter must be declared as OUTPUT.
• For a stored procedure executed using the Transact-SQL EXECUTE statement, the parameter must be declared as OUTPUT.
• For a stored procedure executed using DB-Library functions (such as dbrpcinit), when the parameter is added using dbrpcparam, the status bitmask must contain the DBRPCRETURN option.

If a stored procedure is executed using DB-Library functions (such as dbrpcinit), the return parameter values are automatically available to the application. If the stored procedure is invoked with an EXECUTE statement, the return-parameter values are available only if the command batch containing the EXECUTE statement uses Transact-SQL local variables, not constants, for the return parameters.

See Also