INFORMIX-ESQL/C Programmer's Manual ESQL/C Function Library

The rtypmsize() function returns the number of bytes you must allocate in memory for the specified ESQL/C or SQL data type.

mint rtypmsize(sqltype,  sqllen)

	mint  sqltype;

	mint  sqllen;

 



sqltype  

is the integer code of the ESQL/C or SQL data type. For more information, see Data Type Constants.


sqllen

is the number of bytes in the data file for the specified data type. 

The rtypalign() and rtypmsize() functions are useful when you use an sqlda structure to dynamically fetch data into a buffer. These functions provide machine independence for the column-data storage.

Informix provides the rtypmsize() function to use with the sqlda structure that a DESCRIBE statement initializes. After a DESCRIBE statement determines column information, the value of sqltype and sqllen components reside in the components of the same name in each sqlda.sqlvar structure.

When rtypmsize() determines sizes for character data, keep the following size information in mind:

• For CCHARTYPE (char) and CSTRINGTYPE (string), ESQL/C adds one byte to the number of characters for the null terminator.
• For CFIXCHARTYPE (fixchar), ESQL/C does not add a null terminator.

You can see an application of the rtypmsize() function in the unload.ec demonstration program.

This sample program is in the rtypmsize.ec file in the demo directory.

/*
* rtypmsize.ec *

This program prepares a select statement on all columns of the
catalog table. Then it displays the data type of each column and
the number of bytes needed to store it in memory.
*/

#include <stdio.h>

EXEC SQL include sqltypes;

#define WARNNOTIFY 1
#define NOWARNNOTIFY 0

EXEC SQL BEGIN DECLARE SECTION;
char db_name[20];
EXEC SQL END DECLARE SECTION;

main(argc, argv)
int argc;
char *argv[];
{
mint i;
char db_stmnt[50];
int4 exp_chk();
struct sqlda *sql_desc;
struct sqlvar_struct *col;

printf("RTYPMSIZE Sample ESQL Program running.\n\n");

if (argc > 2) /* correct no. of args? */
{
printf("\nUsage: %s [database]\nIncorrect no. of argument(s)\n",
argv[0]);
exit(1);
}
strcpy(db_name, "stores7");
if (argc == 2)
strcpy(db_name, argv[1]);

EXEC SQL connect to :db_name;
sprintf(db_stmnt, "CONNECT TO %s", argv[1]);
exp_chk(db_stmnt, NOWARNNOTIFY);

printf("Connected to '%s' database.", db_name);

EXEC SQL prepare query_1 from 'select * from catalog'; /* prepare select */
if(exp_chk("Prepare", WARNNOTIFY) == 1)
exit(1);
EXEC SQL describe query_1 into sql_desc; /* setup sqlda */
if(exp_chk("Describe", WARNNOTIFY) == 1)
exit(1);
printf("\n\tColumn Type Size\n\n"); /* column hdgs. */
/*
* For each column in the catalog table display the column name and
* the number of bytes needed to store the column in memory.
*/
for(i = 0, col = sql_desc->sqlvar; i < sql_desc->sqld; i++, col++)
printf("\t%-20s%-8s%3d\n", col->sqlname, rtypname(col->sqltype),
rtypmsize(col->sqltype, col->sqllen));

printf("\nRTYPMSIZE Sample Program over.\n\n");
}

/*
* The exp_chk() file contains the exception handling functions to
* check the SQLSTATE status variable to see if an error has occurred
* following an SQL statement. If a warning or an error has
* occurred, exp_chk() executes the GET DIAGNOSTICS statement and
* prints the detail for each exception that is returned.
*/
EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see Guide to the exp_chk.ec File or refer to the exp_chk.ec file for a listing of this exception-handling function.

RTYPMSIZE Sample ESQL Program running.



Connected to stores7 database.

 


Column
Type
Size





catalog_num
serial   
4

stock_num
smallint
2

manu_code
char
4

cat_descr
text
64

cat_picture
byte
64

cat_advert
varchar
256






RTYPMSIZE Sample Program over.