Build dates now follow SOURCE_DATE_EPOCH specs

See https://reproducible-builds.org/specs/source-date-epoch/

.gitignore

@@ -5,4 +5,4 @@ install*
 *.layout
 CMakeFiles/
 CMakeLists.txt.user
-
+SOURCE_DATE_EPOCH

apps/2d-slam-demo/CAboutBox.cpp

@@ -148,7 +148,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "For bug reports or to collaborate: <joseluisblancoc@gmail.com>\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
  		cout << "OpenCV version:         ";

apps/GridmapNavSimul/CAboutBox.cpp

@@ -146,7 +146,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 
 		cout << "Version:                " << GRIDMAPSIMUL_VERSION << endl;
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
     }

apps/RawLogViewer/CAboutBox.cpp

@@ -145,7 +145,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "http://www.isa.uma.es/jlblanco\n\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
 		cout << "wxMathPlot version:     0.1.2\n";

apps/SceneViewer3D/CAboutBox.cpp

@@ -153,7 +153,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "http://www.isa.uma.es/jlblanco\n\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
 		cout << "wxMathPlot version:     0.03\n";

apps/camera-calib/CAboutBox.cpp

@@ -146,7 +146,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 
 		cout << "Program version:        " << CAMERA_CALIB_GUI_VERSION << endl;
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
  		cout << "OpenCV version:         ";

apps/grid-matching/grid-matching_main.cpp

@@ -717,7 +717,7 @@ int main(int argc, char **argv)
 		if (!arg_nologo.getValue())
 		{
 			printf(" grid-matching - Part of the MRPT\n");
-			printf(" MRPT C++ Library: %s - BUILD DATE %s\n", mrpt::system::MRPT_getVersion().c_str(), mrpt::system::MRPT_getCompilationDate().c_str());
+			printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", mrpt::system::MRPT_getVersion().c_str(), mrpt::system::MRPT_getCompilationDate().c_str());
 		}
 
 		SKIP_ICP_STAGE = arg_skip_icp.getValue();

apps/hmt-slam-gui/CAboutBox.cpp

@@ -144,7 +144,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "For bug reports or to collaborate: <joseluisblancoc@gmail.com>\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
  		cout << "OpenCV version:         ";

apps/hmt-slam/hmt-slam_main.cpp

@@ -51,7 +51,7 @@ int main(int argc, char **argv)
 		CConsoleRedirector	dbg_out_file("./DEBUG_log_streaming.txt",true, true,false,0 );
 
 		printf(" HMT-SLAM version 0.2 - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str() );
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str() );
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/holonomic-navigator-demo/CAboutBox.cpp

@@ -146,7 +146,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "    http://www.mrpt.org/    \n\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
     }

apps/icp-slam-live/icp-slam-live_main.cpp

@@ -53,7 +53,7 @@ int main(int argc, char **argv)
 		bool showVersion = argc>1 && !os::_strcmp(argv[1],"--version");
 
 		printf(" icp-slam-live - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		if (showVersion)
 			return 0;	// Program end
 		printf("-------------------------------------------------------------------\n");

apps/icp-slam/icp-slam_main.cpp

@@ -57,7 +57,7 @@ int main(int argc, char **argv)
 		bool showVersion = argc>1 && !os::_strcmp(argv[1],"--version");
 
 		printf(" icp-slam - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 
 		if (showVersion)
 			return 0;	// Program end

apps/kf-slam/kf-slam_main.cpp

@@ -59,7 +59,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" kf-slam - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/kinect-stereo-calib/CAboutBox.cpp

@@ -147,7 +147,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "For bug reports or to collaborate: <joseluisblancoc@gmail.com>\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
  		cout << "OpenCV version:         ";

apps/map-partition/map-partition.cpp

@@ -318,7 +318,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" map-partition version 0.2 - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/navlog-viewer/CAboutBox.cpp

@@ -149,7 +149,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 
 		cout << "Program version:        " << NAVLOGVIEWER_VERSION << endl;
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
  		cout << "OpenCV version:         ";

apps/observations2map/observations2map_main.cpp

@@ -43,7 +43,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" observations2map - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/pf-localization/pf_localization_main.cpp

@@ -75,7 +75,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" pf-localization\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/rawlog-grabber/rawloggrabber_main.cpp

@@ -72,7 +72,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" rawlog-grabber - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/rbpf-slam/rbpf-slam.cpp

@@ -80,7 +80,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" rbpf-slam - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/ro-localization/ro-localization_main.cpp

@@ -892,7 +892,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" ro-localization - Version 0.1 - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// Process arguments:

apps/robotic-arm-kinematics/CAboutBox.cpp

@@ -147,7 +147,7 @@ void CAboutBox::OnInit(wxInitDialogEvent& event)
 		cout << "    http://www.mrpt.org/    \n\n";
 
 		cout << "MRPT version:           " << MRPT_getVersion() << endl;
-		cout << "MRPT compilation date:  " << MRPT_getCompilationDate() << endl;
+		cout << "MRPT source timestamp:  " << MRPT_getCompilationDate() << endl;
  		cout << "Eigen version:          " << EIGEN_WORLD_VERSION << "." << EIGEN_MAJOR_VERSION << "." << EIGEN_MINOR_VERSION << endl;
 		cout << "wxWidgets version:      " <<std::string(wxVer.mb_str()) << endl;
     }

apps/simul-beacons/simul-beacons-main.cpp

@@ -38,7 +38,7 @@ int main(int argc, char ** argv)
 		bool showVersion = argc>1 && !os::_strcmp(argv[1],"--version");
 
 		printf(" simul-beacons - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 
 		if (showVersion)
 			return 0;	// Program end

apps/simul-gridmap/simul-gridmap_main.cpp

@@ -76,7 +76,7 @@ int main(int argc, char ** argv)
 		if (arg_nologo.getValue())
 		{
 			printf(" simul-gridmap - Part of the MRPT\n");
-			printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+			printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 		}
 
 		// Invoke method:

apps/simul-landmarks/simul-landmarks-main.cpp

@@ -47,7 +47,7 @@ int main(int argc, char ** argv)
 		bool showVersion = argc>1 && !os::_strcmp(argv[1],"--version");
 
 		printf(" simul-landmarks - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
 
 		if (showVersion)
 			return 0;	// Program end

apps/track-video-features/track-video-feats_main.cpp

@@ -369,7 +369,7 @@ int main(int argc, char **argv)
 	try
 	{
 		printf(" track-video-features - Part of MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", mrpt::system::MRPT_getVersion().c_str(), mrpt::system::MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", mrpt::system::MRPT_getVersion().c_str(), mrpt::system::MRPT_getCompilationDate().c_str());
 		printf("-------------------------------------------------------------------\n");
 
 		// The video source:

apps/velodyne-view/velodyne-view_main.cpp

@@ -146,7 +146,7 @@ int VelodyneView(int argc, char **argv)
 	if (!arg_nologo.isSet())
 	{
 		printf(" velodyne-view - Part of the MRPT\n");
-		printf(" MRPT C++ Library: %s - BUILD DATE %s\n", mrpt::system::MRPT_getVersion().c_str(), mrpt::system::MRPT_getCompilationDate().c_str());
+		printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", mrpt::system::MRPT_getVersion().c_str(), mrpt::system::MRPT_getCompilationDate().c_str());
 	}
 
 	// Launch grabbing thread:

cmakemodules/script_create_version_h.cmake

@@ -7,11 +7,38 @@ SET(CMAKE_MRPT_COMPLETE_NAME "MRPT ${CMAKE_MRPT_VERSION_NUMBER_MAJOR}.${CMAKE_MR
 # Build a three digits version code, eg. 0.5.1 -> 051,  1.2.0 -> 120
 SET(CMAKE_MRPT_VERSION_CODE "0x${CMAKE_MRPT_VERSION_NUMBER_MAJOR}${CMAKE_MRPT_VERSION_NUMBER_MINOR}${CMAKE_MRPT_VERSION_NUMBER_PATCH}")
 
-IF (CMAKE_VERSION VERSION_GREATER 2.8.10)
-	STRING(TIMESTAMP CMAKE_MRPT_BUILD_DATE "%Y-%m-%d")
-ELSE()
-	SET(CMAKE_MRPT_BUILD_DATE "")
-ENDIF()
+# SOURCE_DATE_EPOCH: See Specs in https://reproducible-builds.org/specs/source-date-epoch/
+# Take its value from: 
+# 1) The file SRC/SOURCE_DATE_EPOCH  (generated by scripts creating Windows/Debian packages)
+# 2) The env var "SOURCE_DATE_EPOCH"
+# 3) The output from "git log -1 --pretty=%ct"
+# 4) As a last resort, leave it blank, so the C++ source code will use current time.
+
+SET(CMAKE_SOURCE_DATE_EPOCH "")
+# 1: SRC/SOURCE_DATE_EPOCH
+if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/SOURCE_DATE_EPOCH")
+  FILE(STRINGS "${CMAKE_CURRENT_SOURCE_DIR}/SOURCE_DATE_EPOCH" CMAKE_SOURCE_DATE_EPOCH LIMIT_COUNT 1) # Read only the first line
+endif()
+if ("" STREQUAL "${CMAKE_SOURCE_DATE_EPOCH}")
+  # If empty: 
+  # 2) The env var "SOURCE_DATE_EPOCH"
+  if (DEFINED ENV{SOURCE_DATE_EPOCH})
+    set(CMAKE_SOURCE_DATE_EPOCH "$ENV{SOURCE_DATE_EPOCH}")
+  else()
+    # 3) The output from "git log -1 --pretty=%ct"
+    find_package(Git QUIET)
+    if(GIT_FOUND)
+      execute_process(
+        COMMAND "${GIT_EXECUTABLE}" "log" "-1" "--pretty=%ct"
+        OUTPUT_VARIABLE CMAKE_SOURCE_DATE_EPOCH
+        OUTPUT_STRIP_TRAILING_WHITESPACE)
+        IF ($ENV{VERBOSE})
+         MESSAGE(STATUS "SOURCE_DATE_EPOCH from git log: ${CMAKE_SOURCE_DATE_EPOCH}")
+        ENDIF()
+    endif()
+  endif()
+endif()
+
 
 CONFIGURE_FILE("${CMAKE_SOURCE_DIR}/parse-files/version.h.in" "${MRPT_CONFIG_FILE_INCLUDE_DIR}/mrpt/version.h")
 

cmakemodules/script_show_final_summary.cmake

@@ -62,6 +62,11 @@ MESSAGE(STATUS " Word size (32/64 bit)       : ${CMAKE_MRPT_WORD_SIZE}")
 MESSAGE(STATUS " CMake version               : " ${CMAKE_VERSION})
 MESSAGE(STATUS " CMake generator             : "  ${CMAKE_GENERATOR})
 MESSAGE(STATUS " CMake build tool            : " ${CMAKE_BUILD_TOOL})
+if (UNIX)
+  execute_process(COMMAND "date" "-u" "-d" "@${CMAKE_SOURCE_DATE_EPOCH}" "+%Y-%m-%d" OUTPUT_VARIABLE MRPT_BUILD_DATE OUTPUT_STRIP_TRAILING_WHITESPACE)
+endif(UNIX)
+MESSAGE(STATUS " MRPT SOURCE_DATE_EPOCH      : " ${CMAKE_SOURCE_DATE_EPOCH} " (${MRPT_BUILD_DATE})")
+
 MESSAGE(STATUS " Compiler                    : " ${CMAKE_CXX_COMPILER_ID})
 if(MSVC)
 	MESSAGE(STATUS " MSVC                        : " ${MSVC_VERSION})

libs/base/include/mrpt/system/os.h

@@ -141,19 +141,16 @@ namespace mrpt
 		/** \addtogroup mrpt_system_os
 		  * @{ */
 
-		/** Shows the message "Press any key to continue" (or other custom message) to the current standard output and returns when a key is pressed.
-		  */
+		/** Shows the message "Press any key to continue" (or other custom message) to the current standard output and returns when a key is pressed */
 		void BASE_IMPEXP pause(const std::string &msg = std::string("Press any key to continue...") ) MRPT_NO_THROWS;
 
 		/** Clears the console window */
 		void BASE_IMPEXP clearConsole();
 
-		/** Returns the MRPT compilation date
-		  */
+		/** Returns the MRPT source code timestamp, according to the Reproducible-Builds specifications: https://reproducible-builds.org/specs/source-date-epoch/  */
 		std::string BASE_IMPEXP MRPT_getCompilationDate();
 
-		/** Returns a string describing the MRPT version including the SVN number.
-		  */
+		/** Returns a string describing the MRPT version */
 		std::string BASE_IMPEXP MRPT_getVersion();
 
 		/** Returns a const ref to a text with the same text that appears at the beginning of each MRPT file (useful for displaying the License text in GUIs) */

libs/base/src/system/os.cpp

@@ -154,9 +154,31 @@ void mrpt::system::registerFatalExceptionHandlers()
 					mrpt::system::MRPT_getCompilationDate
 ---------------------------------------------------------------*/
 #include <mrpt/version.h>
+#include <errno.h>
+#include <limits.h>
+#include <ctime>
+
 string mrpt::system::MRPT_getCompilationDate()
 {
-	return string( MRPT_build_date_str );
+	time_t now;
+	char *endptr;
+	const char *source_date_epoch = MRPT_SOURCE_DATE_EPOCH;
+
+	errno = 0;
+	unsigned long long epoch = strtoull(source_date_epoch, &endptr, 10);
+	if ((errno == ERANGE && (epoch == ULLONG_MAX || epoch == 0)) || (errno != 0 && epoch == 0)) {
+		// Last resort:
+ 		now = time(NULL);
+	}
+	else {
+		now = epoch;
+	}
+	struct tm *build_time = gmtime(&now);
+	const int year  = build_time->tm_year + 1900;
+	const int month = build_time->tm_mon + 1;
+	const int day   = build_time->tm_mday;
+
+	return mrpt::format("%i-%02i-%02i",year,month,day);
 }
 
 /*---------------------------------------------------------------

mex/apps/mex-grabber/mexgrabber.cpp

@@ -80,7 +80,7 @@ namespace {
 MEX_DEFINE(new) (int nlhs, mxArray* plhs[],
                  int nrhs, const mxArray* prhs[]) {
     printf(" mex-grabber - Part of the MRPT\n");
-    printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+    printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
     printf("-------------------------------------------------------------------\n");
 
     mexplus::InputArguments input(nrhs, prhs, 1);
@@ -297,7 +297,7 @@ int main(int argc, const char* argv[] )
     try
     {
         printf(" MEX-grabber - Part of the MRPT\n");
-        printf(" MRPT C++ Library: %s - BUILD DATE %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
+        printf(" MRPT C++ Library: %s - Sources timestamp: %s\n", MRPT_getVersion().c_str(), MRPT_getCompilationDate().c_str());
         printf("-------------------------------------------------------------------\n");
         printf(" This is a test for Matlab MEX functionalities\n");
         printf("-------------------------------------------------------------------\n");

parse-files/version.h.in

@@ -6,10 +6,11 @@
 #define  MRPT_VERSION_H
 
 const char MRPT_version_str[]    = "${CMAKE_MRPT_COMPLETE_NAME}";
-const char MRPT_build_date_str[] = "${CMAKE_MRPT_BUILD_DATE}";
-
 /** Version number of package in hexadecimal:
   * A three digits version code, eg. 0.5.1 -> 0x051,  1.2.0 -> 0x120 */
 #define MRPT_VERSION ${CMAKE_MRPT_VERSION_CODE}
 
+// See specs: https://reproducible-builds.org/specs/source-date-epoch/
+const char MRPT_SOURCE_DATE_EPOCH[] = "${CMAKE_SOURCE_DATE_EPOCH}";
+
 #endif