dbadlen

Description

Return the actual length of the data for a compute column.

Syntax

DBINT dbadlen(dbproc, computeid, column)
 
DBPROCESS      *dbproc;
int                        computeid;
int                        column;

Parameters

dbproc: A pointer to the DBPROCESS structure that provides the connection for a particular front-end/server process. It contains all the information that DB-Library uses to manage communications and data between the front end and server.

computeid: The ID that identifies the particular compute row of interest. A SQL select statement may have multiple compute clauses, each of which returns a separate compute row. The computeid corresponding to the first compute clause in a select is 1. The computeid is returned by dbnextrow or dbgetrow.

column: The number of the column of interest. The first column is number 1.

Returns

The length, in bytes, of the data for a particular compute column. If there is no such column or compute clause, dbadlen returns -1. If the data has a null value, dbadlen returns 0.

Usage

This routine returns the actual length of the data for a particular compute column.
Use the dbaltlen routine to determine the maximum possible length for the data. Use dbadata to get a pointer to the data.

Here is a program fragment that illustrates the use of dbadlen:

 DBPROCESS     *dbproc;

 char          biggest_name[MAXNAME+1];

 int           namelen;

 int           rowinfo;

 /* put the command into the command buffer */

 dbcmd(dbproc, "select name from sysobjects");

 dbcmd(dbproc, " order by name");

 dbcmd(dbproc, " compute max(name)");

/*

 ** Send the command to Adaptive Server and start

 ** execution.

*/

 dbsqlexec(dbproc);

 /* process the command */

 dbresults(dbproc);

 /* examine each row returned by the command */

 while ((rowinfo = dbnextrow(dbproc)) !=

      NO_MORE_ROWS)

      if (rowinfo == REG_ROW)

         printf("regular row returned.\n");

      else

/*

         ** This row is the result of a compute

         ** clause, and "rowinfo" is the computeid

         ** of this compute clause.

*/

          namelen = dbadlen(dbproc, rowinfo, 1);

          strncpy(biggest_name,

           (char *)dbadata(dbproc, rowinfo, 1),

           namelen);

/*

         ** Data pointed to by dbadata() is not

         ** null-terminated.

*/

         biggest_name[namelen] = ’\0’;

         printf("biggest name = %s\n",

 biggest_name);