diff --git a/.gitignore b/.gitignore
index 526ac83..378eac2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1 @@
-one-sided
-main
-persistent
+build
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f5239c1..eb8eca8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -106,6 +106,13 @@ if (MPI_FOUND)
   set_cxx_standard(one-sided)
 endif()
 
+if (MPI_FOUND)
+  add_executable(persistent persistent.cpp)
+  target_link_libraries(persistent MPI::MPI_CXX)
+  set_cxx_options(persistent)
+  set_cxx_standard(persistent)
+endif()
+
 if (MPI_FOUND AND CMAKE_CUDA_COMPILER)
   add_executable(one-sided-gpu one_sided_gpu.cpp)
   target_link_libraries(one-sided-gpu MPI::MPI_CXX)
diff --git a/README.md b/README.md
index fa3a85c..7919634 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,11 @@
 # mpi_test
 
 Various standalone MPI binaries, either tests or examples depending on your perspective.
-The goal is to compile with no warnings with `-Wall -Wextra -Wshadow -pedantic` or similarly picky settings.
-
-Adjust `Makefile` to match your environment, if needed
-* uses `mpicxx` and a few simple flags by default
 
 ## Build
 ```
+mkdir build && cd build
+cmake ..
 make
 ```
 
diff --git a/one_sided_gpu.cpp b/one_sided_gpu.cpp
index 2c08dd5..9754c80 100644
--- a/one_sided_gpu.cpp
+++ b/one_sided_gpu.cpp
@@ -27,14 +27,6 @@ int main(int argc, char **argv) {
   MPI_Comm_rank(MPI_COMM_WORLD, &rank);
   MPI_Comm_size(MPI_COMM_WORLD, &size);
 
-  // expect our a to be set by the left
-  int source;
-  if (0 == rank) {
-    source = size - 1;
-  } else {
-    source = rank - 1;
-  }
-
   int target; // set the right
   if (rank == size - 1) {
     target = 0;
diff --git a/persistent.cpp b/persistent.cpp
index 6f149d6..c1b395a 100644
--- a/persistent.cpp
+++ b/persistent.cpp
@@ -1,7 +1,8 @@
-#include <mpi.h>
 #include <cstdio>
 #include <vector>
+#include <cstdlib>
 
+#include <mpi.h>
 #include <sys/mman.h>
 #include <errno.h>