.\" -*- nroff -*-
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" $COPYRIGHT$
.TH MPI_Info_get_nkeys 3 "Dec 18, 2020" "4.1.0" "Open MPI"
.SH NAME
\fBMPI_Info_get_nkeys\fP \- Gets the number of keys currently defined in an info object.

.SH SYNTAX
.ft R
.SH C Syntax
.nf
#include <mpi.h>
int MPI_Info_get_nkeys(MPI_Info \fIinfo\fP, int \fI*nkeys\fP)

.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_INFO_GET_NKEYS(\fIINFO, NKEYS, IERROR\fP)
	INTEGER		\fIINFO, NKEYS, IERROR\fP

.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_Info_get_nkeys(\fIinfo\fP, \fInkeys\fP, \fIierror\fP)
	TYPE(MPI_Info), INTENT(IN) :: \fIinfo\fP
	INTEGER, INTENT(OUT) :: \fInkeys\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH C++ Syntax
.nf
#include <mpi.h>
int MPI::Info::Get_nkeys() const

.fi
.SH INPUT PARAMETER
.ft R
.TP 1i
info
Info object (handle).

.SH OUTPUT PARAMETERS
.ft R
.TP 1i
nkeys
Number of defined keys (integer).
.ft R
.TP 1i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
MPI_Info_get_nkeys returns the number of currently defined keys in \fIinfo\fP.

.SH ERRORS
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.
.sp
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.

.SH SEE ALSO
.ft r
MPI_Info_get
.br
MPI_Info_get_nthkey
.br
MPI_Info_get_valuelen
.br