The mi_fparam_get_current() function
The mi_fparam_get_current() function obtains the MI_FPARAM structure for the currently running user-defined routine (UDR).
Syntax
MI_FPARAM *mi_fparam_get_current(void)| Valid in client LIBMI application? | Valid in user-defined routine? |
|---|---|
| No | Yes |
Important: This advanced function can adversely
affect your UDR if you use the function incorrectly. Use it only when
no regular DataBlade®
API function
can perform the task you need done.
Usage
The mi_fparam_get_current() function obtains the MI_FPARAM structure for the current UDR. When the routine manager invokes a UDR, it passes this MI_FPARAM structure as that last argument to the UDR. This function is valid only within a UDR call. It returns the NULL-valued pointer if called from a callback (such as an end-of-statement callback) that is not strictly called from a UDR.
The database server's routine manager allocates
an MI_FPARAM structure for every UDR, regardless of whether
the UDR explicitly declares one or not. If a UDR does not declare
an MI_FPARAM structure but dynamically determines that it requires MI_FPARAM information,
the UDR can use the mi_fparam_get_current() function
to obtain a pointer to its MI_FPARAM structure. This function
is useful when the C function that implements a UDR needs to determine
how many arguments the UDR was registered with (or called with).
Important: If you know that a UDR needs information in the MI_FPARAM structure,
declare an MI_FPARAM structure as the final argument for the
UDR. Restrict use of mi_fparam_get_current() to
UDRs that must dynamically determine that they need MI_FPARAM information.
For more information about how to declare an MI_FPARAM argument or how to obtain routine information for a UDR, see the Informix® DataBlade® API Programmer's Guide.
Return values
- An MI_FPARAM pointer
- A pointer that references the MI_FPARAM structure for the current UDR.
- NULL
- The function was not successful or that it was called from a callback that was not strictly called from a UDR.