# Name

`MPI_Comm_connect` - Establishes communication with a server.

# Syntax

## C Syntax

```c
#include <mpi.h>

int MPI_Comm_connect(const char *port_name, MPI_Info info, int root,
	MPI_Comm comm, MPI_Comm *newcomm)
```

## Fortran Syntax

```fortran
USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_COMM_CONNECT(PORT_NAME, INFO, ROOT, COMM, NEWCOMM, IERROR)
    CHARACTER*(*)	PORT_NAME
    INTEGER		INFO, ROOT, COMM, NEWCOMM, IERROR
```

## Fortran 2008 Syntax

```fortran
USE mpi_f08

MPI_Comm_connect(port_name, info, root, comm, newcomm, ierror)
    CHARACTER(LEN=*), INTENT(IN) :: port_name
    TYPE(MPI_Info), INTENT(IN) :: info
    INTEGER, INTENT(IN) :: root
    TYPE(MPI_Comm), INTENT(IN) :: comm
    TYPE(MPI_Comm), INTENT(OUT) :: newcomm
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror
```

# Input Parameters

* `port_name` : Port name (string, used only on *root*).
* `info` : Options given by root for the connect (handle, used only on root).
No options currently supported.
* `root` : Rank in *comm* of root node (integer).
* `comm` : Intracommunicator over which call is collective (handle).

# Output Parameters

* `newcomm` : Intercommunicator with client as remote group (handle)
* `IERROR` : Fortran only: Error status (integer).

# Description

`MPI_Comm_connect` establishes communication with a server specified by
`port_name`. It is collective over the calling communicator and returns
an intercommunicator in which the remote group participated in an
`MPI_Comm_accept`. The `MPI_Comm_connect` call must only be called after the
`MPI_Comm_accept` call has been made by the MPI job acting as the server.
If the named port does not exist (or has been closed), `MPI_Comm_connect`
raises an error of class `MPI_ERR_PORT`.
MPI provides no guarantee of fairness in servicing connection attempts.
That is, connection attempts are not necessarily satisfied in the order
in which they were initiated, and competition from other connection
attempts may prevent a particular connection attempt from being
satisfied.
The `port_name` parameter is the address of the server. It must be the
same as the name returned by `MPI_Open_port` on the server.

# Errors

Almost all MPI routines return an error value; C routines as the value
of the function and Fortran routines in the last argument.
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.
See the MPI man page for a full list of MPI error codes.

# See Also

[`MPI_Comm_accept`(3)](MPI_Comm_accept.html) 
[`MPI_Open_port`(3)](MPI_Open_port.html)