Informix DataBlade API Programmer's Manual DataBlade API Function Descriptions

The mi_fp_setreturnisnull() accessor function sets the value of a return value of a user-defined function to an SQL NULL in its associated MI_FPARAM structure.

void mi_fp_setreturnisnull(fparam_ptr, ret_pos, is_null)

MI_FPARAM *fparam_ptr;

mi_integer ret_pos;

mi_integer is_null;

fparam_ptr	is a pointer to the associated MI_FPARAM structure.
ret_pos	is the index position into the null-return array for the return value that you want to set to NULL. For C user-defined functions, the only valid value is 0.
is_null	is 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.

Valid in Client LIBMI Application?	Valid in User-Defined Routine?
Yes	Yes

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.

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

For example, the following call to mi_fp_setreturnisnull() sets to NULL the first return value of the my_func() UDR, with which fparam1 is associated:

mi_integer my_func(...., fparam1)
	

	MI_FPARAM *fparam1;
{
	

	mi_fp_setreturnisnull(fparam1, 0, MI_TRUE);


Important: C user-defined functions always have only one return value. 

None.

See the descriptions of the following functions: mi_fp_argisnull(), mi_fp_setargisnull(), mi_fp_setretlen(), mi_fp_setretprec(), mi_fp_setretscale(), and mi_fp_setrettype().