Trying to add parallel for loops (with pthread)

- OpenCV lib compiled with PTHREADS_PF=ON
- Copied and tested in esp32/examples/esp_opencv_tests/
- TODO: Problem while linking pthreads :
        undefined reference to `pthread_cond_signal`

CMakeLists.txt

@@ -604,7 +604,7 @@ ocv_cmake_hook(POST_COMPILER_OPTIONS)
 # ----------------------------------------------------------------------------
 #       CHECK FOR SYSTEM LIBRARIES, OPTIONS, ETC..
 # ----------------------------------------------------------------------------
-if(UNIX)
+if(UNIX OR ESP32)
   if(NOT APPLE_FRAMEWORK OR OPENCV_ENABLE_PKG_CONFIG)
     if(CMAKE_CROSSCOMPILING AND NOT DEFINED ENV{PKG_CONFIG_LIBDIR} AND NOT DEFINED ENV{PKG_CONFIG_SYSROOT_DIR}
         AND NOT OPENCV_ENABLE_PKG_CONFIG

README.md

@@ -84,7 +84,7 @@ cmake 									\
 -DWITH_IPP=OFF 							\
 -DWITH_TBB=OFF 							\
 -DWITH_OPENMP=OFF 						\
--DWITH_PTHREADS_PF=OFF 					\
+-DWITH_PTHREADS_PF=ON 					\
 -DWITH_QUIRC=OFF 						\
 -DWITH_1394=OFF 						\
 -DWITH_CUDA=OFF 						\

esp32/examples/esp_opencv_tests/main/opencv/opencv2/cvconfig.h

@@ -116,10 +116,10 @@
 #define HAVE_PNG
 
 /* Posix threads (pthreads) */
-/* #undef HAVE_PTHREAD */
+#define HAVE_PTHREAD
 
 /* parallel_for with pthreads */
-/* #undef HAVE_PTHREADS_PF */
+#define HAVE_PTHREADS_PF
 
 /* Qt support */
 /* #undef HAVE_QT */

esp32/lib/opencv/opencv2/cvconfig.h

@@ -116,10 +116,10 @@
 #define HAVE_PNG
 
 /* Posix threads (pthreads) */
-/* #undef HAVE_PTHREAD */
+#define HAVE_PTHREAD
 
 /* parallel_for with pthreads */
-/* #undef HAVE_PTHREADS_PF */
+#define HAVE_PTHREADS_PF
 
 /* Qt support */
 /* #undef HAVE_QT */

esp32/scripts/build_opencv_for_esp32.sh

@@ -40,7 +40,7 @@ else
 fi
 
 
-CMAKE_ARGS="-DCMAKE_BUILD_TYPE=Release -DESP32=ON -DBUILD_SHARED_LIBS=OFF -DCV_DISABLE_OPTIMIZATION=OFF -DWITH_IPP=OFF -DWITH_TBB=OFF -DWITH_OPENMP=OFF -DWITH_PTHREADS_PF=OFF -DWITH_QUIRC=OFF -DWITH_1394=OFF -DWITH_CUDA=OFF -DWITH_OPENCL=OFF -DWITH_OPENCLAMDFFT=OFF -DWITH_OPENCLAMDBLAS=OFF -DWITH_VA_INTEL=OFF -DWITH_EIGEN=OFF -DWITH_GSTREAMER=OFF -DWITH_GTK=OFF -DWITH_JASPER=OFF -DWITH_JPEG=OFF -DWITH_WEBP=OFF -DBUILD_ZLIB=ON -DBUILD_PNG=ON -DWITH_TIFF=OFF -DWITH_V4L=OFF -DWITH_LAPACK=OFF -DWITH_ITT=OFF -DWITH_PROTOBUF=OFF -DWITH_IMGCODEC_HDR=OFF -DWITH_IMGCODEC_SUNRASTER=OFF -DWITH_IMGCODEC_PXM=OFF -DWITH_IMGCODEC_PFM=OFF -DBUILD_LIST=${OPENCV_MODULES_LIST} -DBUILD_JAVA=OFF -DBUILD_opencv_python=OFF -DBUILD_opencv_java=OFF -DBUILD_opencv_apps=OFF -DBUILD_PACKAGE=OFF -DBUILD_PERF_TESTS=OFF -DBUILD_TESTS=OFF -DCV_ENABLE_INTRINSICS=OFF -DCV_TRACE=OFF -DOPENCV_ENABLE_MEMALIGN=OFF -DCMAKE_TOOLCHAIN_FILE=${TOOLCHAIN_CMAKE_PATH}"
+CMAKE_ARGS="-DCMAKE_BUILD_TYPE=Release -DESP32=ON -DBUILD_SHARED_LIBS=OFF -DCV_DISABLE_OPTIMIZATION=OFF -DWITH_IPP=OFF -DWITH_TBB=OFF -DWITH_OPENMP=OFF -DWITH_PTHREADS_PF=ON -DWITH_QUIRC=OFF -DWITH_1394=OFF -DWITH_CUDA=OFF -DWITH_OPENCL=OFF -DWITH_OPENCLAMDFFT=OFF -DWITH_OPENCLAMDBLAS=OFF -DWITH_VA_INTEL=OFF -DWITH_EIGEN=OFF -DWITH_GSTREAMER=OFF -DWITH_GTK=OFF -DWITH_JASPER=OFF -DWITH_JPEG=OFF -DWITH_WEBP=OFF -DBUILD_ZLIB=ON -DBUILD_PNG=ON -DWITH_TIFF=OFF -DWITH_V4L=OFF -DWITH_LAPACK=OFF -DWITH_ITT=OFF -DWITH_PROTOBUF=OFF -DWITH_IMGCODEC_HDR=OFF -DWITH_IMGCODEC_SUNRASTER=OFF -DWITH_IMGCODEC_PXM=OFF -DWITH_IMGCODEC_PFM=OFF -DBUILD_LIST=${OPENCV_MODULES_LIST} -DBUILD_JAVA=OFF -DBUILD_opencv_python=OFF -DBUILD_opencv_java=OFF -DBUILD_opencv_apps=OFF -DBUILD_PACKAGE=OFF -DBUILD_PERF_TESTS=OFF -DBUILD_TESTS=OFF -DCV_ENABLE_INTRINSICS=OFF -DCV_TRACE=OFF -DOPENCV_ENABLE_MEMALIGN=OFF -DCMAKE_TOOLCHAIN_FILE=${TOOLCHAIN_CMAKE_PATH}"
 
 
 ### configure and build opencv ###

modules/core/src/parallel.cpp

@@ -942,7 +942,7 @@ int cv::getNumberOfCPUs(void)
 
 #endif
 
-// esp32 doesn't support sysconf call. FIXME: add support
+// esp32 doesn't support sysconf call. FIXME: add support? Return always 2 (only for ESP32D0WD)
 #if !defined(_WIN32) && !defined(__APPLE__) && !defined(ESP32)
 
     static unsigned cpu_count_sysconf = (unsigned)sysconf( _SC_NPROCESSORS_ONLN );

modules/core/src/parallel_impl.cpp

@@ -7,7 +7,13 @@
 #include "parallel_impl.hpp"
 
 #ifdef HAVE_PTHREADS_PF
+#ifdef __cplusplus
+extern "C" {
+#endif
 #include <pthread.h>
+#ifdef __cplusplus
+}
+#endif
 
 #include <opencv2/core/utils/configuration.private.hpp>