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

The dectodbl() function converts a decimal type number into a C double type number.

mint dectodbl(dec_val,  dbl_val)

	dec_t  *dec_val;

	double  *dbl_val;

 



dec_val  

is a pointer to a decimal structure whose value dectodbl() converts to a double type value.


dbl_val

is a pointer to a double type where dectodbl() places the result of the conversion. 

The floating-point format of the host computer can result in loss of precision in the conversion of a decimal type number to a double type number.

The file dectodbl.ec file in the demo directory contains the following sample program.

/*
* dectodbl.ec *

The following program converts two DECIMAL numbers to doubles and displays
the results.
*/

#include <stdio.h>

EXEC SQL include decimal;

char string1[] = "2949.3829398204382";
char string2[] = "3238299493";
char result[40];

main()
{
mint x;
double d = 0;
dec_t num;

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

if (x = deccvasc(string1, strlen(string1), &num))
{
printf("Error %d in converting string1 to DECIMAL\n", x);
exit(1);
}
if (x = dectodbl(&num, &d))
{
printf("Error %d in converting DECIMAL1 to double\n", x);
exit(1);
}
printf("String 1 = %s\n", string1);
printf("Double value = %.15f\n", d);

if (x = deccvasc(string2, strlen(string2), &num))
{
printf("Error %d in converting string2 to DECIMAL\n", x);
exit(1);
}
if (x = dectodbl(&num, &d))
{
printf("Error %d in converting DECIMAL2 to double\n", x);
exit(1);
}
printf("String 2 = %s\n", string2);
printf("Double value = %f\n", d);

printf("\nDECTODBL Sample Program over.\n\n");
exit(0);
}

DECTODBL Sample ESQL Program running.

String 1 = 2949.3829398204382
Double value = 2949.382939820438423

String 2 = 3238299493
Double value = 3238299493.000000

DECTODBL Sample Program over.