diff --git a/.vscode/launch.json b/.vscode/launch.json
index b097c07..620cc8d 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -4,6 +4,21 @@
   // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
   "version": "0.2.0",
   "configurations": [
+    {
+      "name": "(gdb) Attach",
+      "type": "cppdbg",
+      "request": "attach",
+      "program": "/home/matt/github/mrcal-java/cmake_build/lib/libmrcal_jni.so",
+      "processId": "${command:pickProcess}",
+      "MIMode": "gdb",
+      "setupCommands": [
+        {
+          "description": "Enable pretty-printing for gdb",
+          "text": "-enable-pretty-printing",
+          "ignoreFailures": true
+        }
+      ]
+    },
     {
       "name": "Python debug calibrate cameras",
       "type": "debugpy",
@@ -12,8 +27,19 @@
       "console": "integratedTerminal",
       "cwd": "/home/matt/mrcal_debug_tmp/output_will/images-trimmed",
       "args": [
-        "--corners-cache","corners.vnl","--lensmodel","LENSMODEL_OPENCV8","--focal","1200",
-        "--object-spacing","0.03","--object-width-n","18","--object-height-n","13","*.png"
+        "--corners-cache",
+        "corners.vnl",
+        "--lensmodel",
+        "LENSMODEL_OPENCV8",
+        "--focal",
+        "1200",
+        "--object-spacing",
+        "0.03",
+        "--object-width-n",
+        "18",
+        "--object-height-n",
+        "13",
+        "*.png"
       ],
       "justMyCode": false
     },
@@ -63,4 +89,4 @@
       ]
     }
   ]
-}
\ No newline at end of file
+}
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b8cd135..2799550 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,6 @@ if (WITH_ASAN)
     add_compile_options(-fsanitize=address -g -Wall -fsanitize=undefined)
 endif ()
 
-
 find_package(JNI)
 if (JNI_FOUND)
     # Fixes odd AWT dependency
diff --git a/src/mrcal_wrapper.cpp b/src/mrcal_wrapper.cpp
index 40ce2f8..28d9cc3 100644
--- a/src/mrcal_wrapper.cpp
+++ b/src/mrcal_wrapper.cpp
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) Photon Vision.
- * 
+ *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted.
  *
@@ -115,7 +115,9 @@ static std::unique_ptr<mrcal_result> mrcal_calibrate(
 
   // Copy from board/point pool above, using some code borrowed from
   // mrcal-pywrap
-  mrcal_observation_board_t c_observations_board[Nobservations_board];
+  std::vector<mrcal_observation_board_t> observations_board_data;
+  observations_board_data.resize(Nobservations_board);
+  auto c_observations_board = observations_board_data.data();
   // Try to make sure we don't accidentally make a zero-length array or
   // something stupid
   mrcal_observation_point_t
@@ -176,8 +178,13 @@ static std::unique_ptr<mrcal_result> mrcal_calibrate(
   // call optimize
 
   // Residuals
-  double c_b_packed_final[Nstate];
-  double c_x_final[Nmeasurements];
+  std::vector<double> b_packed_final;
+  b_packed_final.resize(Nstate);
+  auto c_b_packed_final = b_packed_final.data();
+
+  std::vector<double> x_final;
+  x_final.resize(Nmeasurements);
+  auto c_x_final = x_final.data();
 
   // Seeds
   double *c_intrinsics = intrinsics.data();