[Valgrind-users] can memchecker mark memory as read-only ?

[Gilles G. <gil...@gm...>]

Folks,

Currently, my understanding is that valgrind memchecker can mark a
memory area as non accessible via the VALGRIND_MAKE_MEM_NOACCESS()
macro,
but there is currently no way to mark it as read-only.

am i right ?
if yes, is there any plan to develop such a feature ?

Thanks,

Gilles

FWIW, here is the context.
in MPI http://www.mpi-forum.org/, the MPI_Isend() function can be used
for a non blocking send. Today's standard mandates the send buffer
remains accessible during the send operation, but the end user should
not modify it unless the send is complete (for example after
MPI_Wait() returns).
>From an OpenMPI developer point of view, it would be nice to mark the send
buffer as read-only between MPI_Isend() and MPI_Wait() so valgrind can trap
incorrect user code that modifies the send buffer when it is not allowed.