The mi_fp_setreturnisnull() function

Syntax

void mi_fp_setreturnisnull(fparam_ptr, ret_pos, is_null)
   MI_FPARAM *fparam_ptr;
   mi_integer ret_pos;
   mi_integer is_null;

fparam_ptr

A pointer to the associated MI_FPARAM structure.

ret_pos

The index position into the null-return array for the return value to set to NULL. For C user-defined functions, the only valid value is 0.

is_null

The value that determines whether the ret_pos+1 return value is NULL. You can specify the following values for the is_null argument:

MI_FALSE

The return value that ret_pos identifies is not NULL.

MI_TRUE

The return value that ret_pos identifies is NULL.

Usage

The mi_fp_setreturnisnull() function sets the function return value at position ret_pos in the MI_FPARAM structure that fparam_ptr references to the appropriate SQL NULL value. The MI_FPARAM structure stores information about whether function return values are NULL in the zero-based null-return array.

For more information about return-value information in an MI_FPARAM structure, see the Informix® DataBlade® API Programmer's Guide.

To set the nth return value, use a ret_pos value of n-1.

mi_integer my_func(..., fparam1)
...
   MI_FPARAM *fparam1;
{
   ...
   mi_fp_setreturnisnull(fparam1, 0, MI_TRUE);

Return values

None.