G4.2: bridge-side plugin process pool — SandboxVst3Host spawns/respawns plugin_host.exe per channel, MIDI forward + audio snapshot + watchdog mute/respawn, crash isolation verified

native_bridge/src/plugin_host_main.cpp

@@ -34,12 +34,14 @@ int main(int argc, char* argv[]) {
     double sr = 44100.0;
     uint32_t block = AUDIO_BLOCK_SIZE;
     uint32_t parentPid = 0;
+    bool isOpen = false;
     for (int i = 1; i < argc; ++i) {
         if (strcmp(argv[i], "--shm") == 0 && i + 1 < argc) shmName = argv[++i];
         else if (strcmp(argv[i], "--path") == 0 && i + 1 < argc) path = argv[++i];
         else if (strcmp(argv[i], "--sr") == 0 && i + 1 < argc) sr = atof(argv[++i]);
         else if (strcmp(argv[i], "--block") == 0 && i + 1 < argc) block = (uint32_t)atoi(argv[++i]);
         else if (strcmp(argv[i], "--parent") == 0 && i + 1 < argc) parentPid = (uint32_t)strtoul(argv[++i], nullptr, 0);
+        else if (strcmp(argv[i], "--open") == 0) isOpen = true;
     }
     if (shmName.empty() || path.empty()) {
         printf("usage: plugin_host --shm <name> --path <vst3> [--sr rate] [--block n] [--parent pid]\n");
@@ -53,8 +55,8 @@ int main(int argc, char* argv[]) {
            (unsigned long)GetCurrentProcessId(), shmName.c_str(), path.c_str(), sr, block);
     fflush(stdout);
 
-    // PoC: the child owns the mapping. Bridge adoption (G4.2) opens instead.
-    ShmHandle* shm = shm_create(shmName.c_str());
+    // --open: bridge already created the mapping (G4.2); default PoC: child owns.
+    ShmHandle* shm = isOpen ? shm_open(shmName.c_str()) : shm_create(shmName.c_str());
     if (!shm) {
         printf("[plugin_host] FAILED shm_create %s\n", shmName.c_str());
         return 3;