pvm_catchout(3) Catch output from child tasks.


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


File descriptor on which to write collected output.
Integer parameter. Turns output collection on or off.
Integer status code returned by the routine. Values less than zero indicate an error.


The routine pvm_catchout causes the calling task (the parent) to catch output from any 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 their 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 for any subsequently spawned child tasks. (Any existing output collection will still proceed at the child tasks, until they exit or change theirPvmOutputTid or related settings - see man page for pvm_setopt().) In Fortran, output collection can only be turned on or off (again only for subsequently spawned child tasks), and is always logged to the stdout of the parent task.

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

pvm_catchout() always returns 0.


        #include <stdio.h>