ADDHOSTS(3PVM)

NAME
pvm_addhosts - Add hosts to the virtual machine.

SYNOPSIS
C	int info = pvm_addhosts( char **hosts, int nhost, int *infos )
Fortran	call pvmfaddhost( host, info )

PARAMETERS

hosts
    An array of strings naming the hosts to be added. Pvmd must already be installed and the user must have an account on the specified hosts.

nhost
    Integer specifying the length of array hosts.

infos
    Integer array of length nhost which returns the status for each host. Values less than zero indicate an error, while positive values are TIDs of the new hosts.

host
    Character string naming the host to be added.

info
    Integer status code returned by the routine. Values less than nhost indicate partial failure, and values less than 1 indicate total failure.

DESCRIPTION
The routine pvm_addhosts adds the computers named in hosts to the configuration of computers making up the virtual machine. The names should have the same syntax as lines of a pvmd hostfile (see man page for pvmd3): A hostname followed by options of the form xx=y.

If pvm_addhosts is successful, info will be equal to nhost. Partial success is indicated by 0 < info < nhost, and total failure by info < 1. The array infos can be checked to determine which host caused the error.

The Fortran routine pvmfaddhost adds a single host to the configuration with each call. info will be 1 if successful or < 0 if error.

The status of hosts can be requested by the application using pvm_mstat and pvm_config. If a host fails it will be automatically deleted from the configuration. Using pvm_addhosts a replacement host can be added by the application, however it is the responsibility of the application developer to make his application tolerant of host failure. Another use of this feature would be to add more hosts as they become available, for example on a weekend, or if the application dynamically determines it could use more computational power.

EXAMPLES
C:
	static char *hosts[] = {
	    "sparky",
	    "thud.cs.utk.edu",
	};
	info = pvm_addhosts( hosts, 2, infos );

Fortran:
	CALL PVMFADDHOST( 'azure', INFO )

ERRORS
The following error conditions can be returned by pvm_addhosts:

PvmBadParam
    giving an invalid argument value.

PvmAlready
    another task is currently adding hosts.

PvmSysErr
    local pvmd is not responding.

and in the infos vector:

PvmBadParam
    bad hostname syntax.

PvmNoHost
    no such host.

PvmCantStart
    failed to start pvmd on host.

PvmDupHost
    host already configured.

PvmBadVersion
    pvmd protocol versions don't match.

PvmOutOfRes
    PVM has run out of system resources.

SEE ALSO
pvm_pvmd3(1PVM), pvm_delhosts(3PVM), pvm_start_pvmd(3PVM), pvm_config(3PVM), pvm_mstat(3PVM)