MPI_Info_set adds the (key,value) pair to \fIinfo\fP and overrides the value if a value for the same key was previously set. The \fIkey\fP and \fIvalue\fP parameters are null-terminated strings in C. In Fortran, leading and trailing spaces in \fIkey\fP and \fIvalue\fP are stripped. If either \fIkey\fP or \fIvalue\fP is larger than the allowed maximums, the error MPI_ERR_INFO_KEY or MPI_ERR_INFO_VALUE is raised, respectively.
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an MPI::Exception object.
Before the error value is returned, the current MPI error handler is
called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.
