+Added read_variable and read_attribute to MOM_io

  Added the new set of routines read_variable to do a simple read of an entire
array from a netCDF file with the root PE, and then broadcast this information
to the other PEs.  Also added read_attribute to read a global or variable
attribute.  The option to read dimension names was added to get_var_sizes, and
the option for get_varid to indicate whether a variable has been found. As a
part of this, separate variants of broadcast were added for 32-bit and 64-bit
integers, as were new variants of MOM_read_data for 1-d and 0-d integer fields.
All answers are bitwise identical, but there are new options and optional
arguments for overloaded interface, and there are two new overloaded interfaces
for reading.

src/framework/MOM_coms_infra.F90

@@ -23,7 +23,7 @@ module MOM_coms_infra
 
 !> Communicate an array, string or scalar from one PE to others
 interface broadcast
-  module procedure broadcast_char, broadcast_int0D, broadcast_int1D
+  module procedure broadcast_char, broadcast_int32_0D, broadcast_int64_0D, broadcast_int1D
   module procedure broadcast_real0D, broadcast_real1D, broadcast_real2D
 end interface broadcast
 
@@ -129,8 +129,8 @@ subroutine broadcast_char(dat, length, from_PE, PElist, blocking)
 end subroutine broadcast_char
 
 !> Communicate an integer from one PE to others
-subroutine broadcast_int0D(dat, from_PE, PElist, blocking)
-  integer,               intent(inout) :: dat       !< The data to communicate and destination
+subroutine broadcast_int64_0D(dat, from_PE, PElist, blocking)
+  integer(kind=int64),   intent(inout) :: dat       !< The data to communicate and destination
   integer,     optional, intent(in)    :: from_PE   !< The source PE, by default the root PE
   integer,     optional, intent(in)    :: PElist(:) !< The list of participating PEs, by default the
                                                     !! active PE set as previously set via Set_PElist.
@@ -146,7 +146,28 @@ subroutine broadcast_int0D(dat, from_PE, PElist, blocking)
   call mpp_broadcast(dat, src_PE, PElist)
   if (do_block) call mpp_sync_self(PElist)
 
-end subroutine broadcast_int0D
+end subroutine broadcast_int64_0D
+
+
+!> Communicate an integer from one PE to others
+subroutine broadcast_int32_0D(dat, from_PE, PElist, blocking)
+  integer(kind=int32),   intent(inout) :: dat       !< The data to communicate and destination
+  integer,     optional, intent(in)    :: from_PE   !< The source PE, by default the root PE
+  integer,     optional, intent(in)    :: PElist(:) !< The list of participating PEs, by default the
+                                                    !! active PE set as previously set via Set_PElist.
+  logical,     optional, intent(in)    :: blocking  !< If true, barriers are added around the call
+
+  integer :: src_PE   ! The processor that is sending the data
+  logical :: do_block ! If true add synchronizing barriers
+
+  do_block = .false. ; if (present(blocking)) do_block = blocking
+  if (present(from_PE)) then ; src_PE = from_PE ; else ; src_PE = root_PE() ; endif
+
+  if (do_block) call mpp_sync(PElist)
+  call mpp_broadcast(dat, src_PE, PElist)
+  if (do_block) call mpp_sync_self(PElist)
+
+end subroutine broadcast_int32_0D
 
 !> Communicate a 1-D array of integers from one PE to others
 subroutine broadcast_int1D(dat, length, from_PE, PElist, blocking)