CATCHOUT(3PVM)

NAME
pvm_catchout - Catch output from child tasks.

SYNOPSIS
C	#include <stdio.h>
	int info = pvm_catchout( FILE *ff )
Fortran	call pvmfcatchout( onoff, info )

PARAMETERS

ff  File descriptor on which to write collected output.

onoff
    Integer parameter. Turns output collection on or off.

info
    Integer status code returned by the routine. Values less than zero indicate an error.

DESCRIPTION
The routine pvm_catchout causes the calling task (the parent) to catch output from tasks spawned after the call to pvm_catchout. Characters printed on stdout or stderr in children tasks are collected by the pvmds and sent in control messages to the parent task, which tags each line and appends it to the specified file. Output from grandchildren (spawned by children) tasks is also collected, provided the children don't reset PvmOutputTid.

If option PvmShowTids (see pvm_setopt) is true (nonzero), output is printed as shown below, tagged with the task id where the output originated:
	[txxxxx] BEGIN
	[txxxxx] (text from child task)
	[txxxxx] END
The output from each task includes one BEGIN line and one END line, with whatever the task prints in between. If PvmShowTids is false, raw output is printed with no additional information.

In C, the output file descriptor may be specified. Giving a null pointer turns output collection off. In Fortran, output collection can only be turned on or off, and is logged to stdout of the parent task.

If pvm_exit is called while output collection is in effect, it will block until all tasks sending it output have exited, in order to print all their output. To avoid this, output collection can be turned off by calling pvm_catchout(0) before calling pvm_exit.

pvm_catchout() always returns 0.

EXAMPLES
C:
	#include <stdio.h>
	pvm_catchout(stdout);

Fortran:
	CALL PVMFCATCHOUT( 1, INFO )

SEE ALSO
pvm_exit(3PVM), pvm_setopt(3PVM), pvm_spawn(3PVM)