From 387214a3c5551cf061bf7a0643361852f58dc82b Mon Sep 17 00:00:00 2001
From: jiakai <jia.kai66@gmail.com>
Date: Mon, 21 Dec 2015 12:04:00 +0800
Subject: [PATCH] do not open libopencl by dlopen if HAVE_OPENCL is not set

---
 modules/core/src/ocl.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/modules/core/src/ocl.cpp b/modules/core/src/ocl.cpp
index eed4ee5d37..40fa91d984 100644
--- a/modules/core/src/ocl.cpp
+++ b/modules/core/src/ocl.cpp
@@ -685,9 +685,12 @@ typedef struct _cl_buffer_region {
 #define CL_CALLBACK CV_STDCALL
 
 static volatile bool g_haveOpenCL = false;
-static const char* oclFuncToCheck = "clEnqueueReadBufferRect";
 
-#if defined(__APPLE__)
+#ifdef HAVE_OPENCL
+static const char* oclFuncToCheck = "clEnqueueReadBufferRect";
+#endif
+
+#if defined(__APPLE__) && defined(HAVE_OPENCL)
 #include <dlfcn.h>
 
 static void* initOpenCLAndLoad(const char* funcname)
@@ -716,7 +719,7 @@ static void* initOpenCLAndLoad(const char* funcname)
     return funcname && handle ? dlsym(handle, funcname) : 0;
 }
 
-#elif defined WIN32 || defined _WIN32
+#elif (defined WIN32 || defined _WIN32) && defined(HAVE_OPENCL)
 
 #ifndef _WIN32_WINNT           // This is needed for the declaration of TryEnterCriticalSection in winbase.h with Visual Studio 2005 (and older?)
   #define _WIN32_WINNT 0x0400  // http://msdn.microsoft.com/en-us/library/ms686857(VS.85).aspx
@@ -751,7 +754,7 @@ static void* initOpenCLAndLoad(const char* funcname)
     return funcname ? (void*)GetProcAddress(handle, funcname) : 0;
 }
 
-#elif defined(__linux)
+#elif defined(__linux) && defined(HAVE_OPENCL)
 
 #include <dlfcn.h>
 #include <stdio.h>