diff --git a/util/test/demos/test_common.cpp b/util/test/demos/test_common.cpp
index 1fa800f4f..31516d5e4 100644
--- a/util/test/demos/test_common.cpp
+++ b/util/test/demos/test_common.cpp
@@ -297,6 +297,12 @@ bool SpvCompilationSupported()
     if(!pipe)
       continue;
 
+    char dummy[512];
+    while(!feof(pipe))
+    {
+      fread(dummy, 1, 512, pipe);
+    }
+
     int code = pclose(pipe);
 
     if(WEXITSTATUS(code) == 0)
@@ -516,6 +522,12 @@ std::vector<uint32_t> CompileShaderToSpv(const std::string &source_text, SPIRVTa
     return ret;
   }
 
+  char dummy[512];
+  while(!feof(pipe))
+  {
+    fread(dummy, 1, 512, pipe);
+  }
+
   pclose(pipe);
 
   f = fopen(outfile.c_str(), "rb");