bsp_set_tagsize(3)

NAME
bsp_set_tagsize - tag size of a BSMP packet.

C SYNOPSIS
#include "bsp.h"

void bsp_set_tagsize(int *tag_bytes);

FORTRAN SYNOPSIS
SUBROUTINE  bspsettagsize(tag_bytes)
  INTEGER, intent(INOUT) :: tag_bytes

DESCRIPTION
Allowing the user to set the tag size enables the use of tags that are appropriate for the communication requirements of each superstep. This should be particularly useful in the development of subroutines either in user programs or in libraries. The procedure must be called collectively by all processes. A change in tag size takes effect in the following superstep; it then becomes valid . The value of tag_bytes on entry to the procedure, specifies the size of the fixed-length portion of every message in the current and succeeding supersteps; the default tag size is zero. On return from the procedure, tag_bytes is changed to reflect the previous value of the tag size.

SEE ALSO
bsmp(3) ,bsp_send(3), bsp_get_tag(3), bsp_qsize(3), bsp_move(3), bsp_hpmove(3) ``BSPlib: The BSP Programming Library'' Jonathan M. D. Hill, Bill McColl, Dan C. Stefanescu, Mark W. Goudreau, Kevin Lang, Satish B. Rao, , Torsten Suel, Thanasis Tsantilas, and Rob Bisseling. Parallel Computing, to appear 1998. See http://www.bsp-worldwide.org for more details.

NOTES

i   The tag size of outgoing messages is prescribed by the tag size that is valid in the current superstep.

ii  The tag size of messages in the system queue is prescribed by the tag size that was valid in the previous superstep.

iii bsp_set_tagsize(3) must be called by all processes with the same argument in the same superstep. In this respect, it is similar to bsp_push_reg(3) .

iv  bsp_set_tagsize(3) takes effect in the next superstep.

v   Given a sequence of bsp_set_tagsize(3) within the same superstep, then the value of the last of these will be used as the tag size for the next superstep.

vi  The default tag size is 0.

BUGS
Problems and bug reports should be mailed to bsplib-bugs@comlab.ox.ac.uk

AUTHORS
The Oxford BSP Toolset implementation of BSPlib was written by Jonathan.Hill@comlab.ox.ac.uk
http://www.comlab.ox.ac.uk/oucl/people/jonathan.hill.html