The mi_tab_setuserdata() accessor function

Syntax

void mi_tab_setuserdata(MI_AM_TABLE_DESC *tableDesc,
   void *user_data)

tableDesc

Points to the table descriptor.

user_data

Points to a data structure that the access method creates.

Usage

The access method stores state information from one purpose function so that another purpose function can use it.

To save table-state information as user data:

1. Call the appropriate DataBlade API memory-management function to allocate PER_STMT_EXEC or PER_STMT_PREP memory for the user-data structure.
2. Populate the user-data structure with the state information.
3. Call the mi_tab_setuserdata() function to store the pointer that the memory-allocation function returns in the table descriptor.

   Pass the pointer as the user_data argument.

Typically, an access method performs the preceding procedure in the am_open purpose function and deallocates the user-data memory in the am_close purpose function. To have the table descriptor retain the pointer to the user data as long as the table remains open, specify a memory duration of PER_STMT_EXEC or PER_STMT_PREP as Memory-duration options and Persistent user data describe.

To retrieve the pointer from the table descriptor to access the table-state user data, call the mi_tab_userdata() function in any purpose function between am_open and am_close.

Return values

None