unhandled exception error while using Dll

[Deleted_U_Intel]

hi,
There is an access violation error occuring when we try to write to a port using a third party Dll. The error is 0xc0000005.While running the program in debug mode, after the access violation error the program runs to memory location 00000000 and displays '???' beside the address.Could it be a problem with the cray pointer linking to the external function?
-a

[Steven_L_Intel1]

Yes, it could be that. In the debugger, check the address in the pointer before the call to see what it is.

Steve