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)