Error Handlers

When an error occurs as a result of an MPI call, the handler may not run on the same thread as the thread that made the error-raising call. In other words, you cannot assume that the error handler will execute in the local context of the thread that made the error-raising call. The error handler may be executed by another thread on the same process, distinct from the one that returns the error code. Therefore, you cannot rely on local variables for error handling in threads; instead, use global variables from the process.