From 82bab57e98ad690ee8301eff516e600254b1731a Mon Sep 17 00:00:00 2001
From: Julian Hinxlage <hinxlage.julian@web.de>
Date: Thu, 21 Nov 2019 13:03:53 +0100
Subject: [PATCH] ~ segfault bug fix on getPixel

---
 src/SharedMemoryAccess.cpp | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/SharedMemoryAccess.cpp b/src/SharedMemoryAccess.cpp
index 697b5b0..9ea7ba2 100644
--- a/src/SharedMemoryAccess.cpp
+++ b/src/SharedMemoryAccess.cpp
@@ -60,18 +60,26 @@ namespace vkvm {
         unlockSharedMemory();
     }
 
+    char *getLocalMemory(){
+        if (localSharedMemory.empty()) {
+            constexpr int kilo = 1024;
+            localSharedMemory.resize(impl.sharedMemorySize);
+        }
+        return &localSharedMemory[0];
+    }
+
     auto getSharedMemory() -> char * {
         int shmId = shmget(impl.sharedMemoryKey, 0, 0);
         if (shmId < 0) {
             //using a local buffer for shared memory testing
-            if (localSharedMemory.empty()) {
-                initSemaphore();
-                constexpr int kilo = 1024;
-                localSharedMemory.resize(impl.sharedMemorySize * kilo);
-            }
-            return &localSharedMemory[0];
+            return getLocalMemory();
+        }
+        char *ptr =  static_cast<char *>(shmat(shmId, nullptr, 0));
+        if((size_t)ptr == (size_t)-1){
+            return getLocalMemory();
+        }else{
+            return ptr;
         }
-        return static_cast<char *>(shmat(shmId, nullptr, 0));
     }
 
     auto getSharedMemory(char *address, int size, int offset) -> void {