sbcl - how to muffle "undefined variable" warning?

may help you . In elems_[ptr] = data[ptr++], it is undefined whether elems_[ptr] is evaluated first or data[ptr++] is evaluated first. This is so, because = does not introduce a sequence point.
Depending on the order, elems_[ptr] = data[ptr++] yields different results. Hence the warning.

it fixes the issue In answer to your comment that there is a problem with MPI_Bcast. You are calling this function three times.

int MPI_Bcast(void *buffer, int count, MPI_Datatype datatype, int root, MPI_Comm comm)

MPI_Bcast(recvbuffer, totalnums, MPI_INT, 0, MPI_COMM_WORLD);

MPI_Bcast(origsize, 1, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Bcast(totalnums, 1, MPI_INT, 0, MPI_COMM_WORLD);

MPI_Bcast(&origsize, 1, MPI_INT, 0, MPI_COMM_WORLD);
MPI_Bcast(&totalnums, 1, MPI_INT, 0, MPI_COMM_WORLD);

like below fixes the issue The increment is undefined because once i reaches std::numeric_limits::max() (231 - 1 on a 32-bit, LP64 or LLP64 platform), incrementing it will overflow, which is undefined behavior for signed integral types.
gcc is warning on iteration 4294967296ul (232) rather than iteration 2147483646u (231) as you might expect, because it doesn't know the initial value of i; some other code might have run before main to set i to something other than 0. But once main is entered, no other code can run to alter i, and so once 232 iterations have completed it will have at some point reached 231 - 1 and overflowed.

it helps some times The solution wasn't initially obvious and it does feel like an inconsistency in ansible.

  - name: install custom packages for the host if there are any
    apt: pkg={{ item }} state=latest
    with_items: "{{ extra_packages | default([]) }}"

wish of those help In sbcl, I know I can muffle the anticipated messages when using both &optional and &key in defun, but that doesn't seem to work in defmacro. (I should just redesign/rewrite, I know, but this is legacy code.) , You need to run

(declaim (sb-ext:muffle-conditions style-warning))

$ sbcl --non-interactive --eval '(declaim (sb-ext:muffle-conditions style-warning))' --eval '(compile-file "5")'
This is SBCL 1.4.0, an implementation of ANSI Common Lisp.
More information about SBCL is available at <http://www.sbcl.org/>.

SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under
BSD-style licenses.  See the CREDITS and COPYING files in the
distribution for more information.
; compiling file "/Users/sds/lisp/5.lisp" (written 09 OCT 2017 09:51:51 PM):
; compiling (DEFUN WILMA ...)
; compiling (DEFMACRO BETTY ...)

; /Users/sds/lisp/5.fasl written
; compilation finished in 0:00:00.010

(defun wilma (&optional wilma1 &key wilma2 wilma3)
  (declare (ignore wilma1 wilma2 wilma3)))

(defmacro betty (&optional betty1 &key betty2 betty3)
  (declare (ignore betty1 betty2 betty3)))