Fix fcloseall not defined on some platform

CMakeLists.txt

@@ -50,6 +50,13 @@ check_symbol_exists(strerror_r "string.h" HAVE_STRERROR_R)
 if (HAVE_STRERROR_R)
     test_strerror_r(HAVE_GNU_STRERROR_R)
 endif()
+if (NOT WIN32)
+    set(CMAKE_REQUIRED_DEFINITIONS -D_GNU_SOURCE)
+    check_symbol_exists(fcloseall "stdio.h" HAVE_FCLOSEALL)
+    if (HAVE_FCLOSEALL)
+        add_compile_definitions(_GNU_SOURCE)
+    endif()
+endif()
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/utils_config.h.in" "${CMAKE_CURRENT_BINARY_DIR}/utils_config.h")
 
 if (${CMAKE_C_COMPILER_ID} STREQUAL GNU)

fileop.cpp

@@ -539,7 +539,9 @@ std::string fileop::filename(std::string path) {
 int fileop::fcloseall() {
 #if _WIN32
     return ::_fcloseall();
-#else
+#elif HAVE_FCLOSEALL
     return ::fcloseall();
+#else
+    return 0;
 #endif
 }

fileop.h

@@ -171,6 +171,7 @@ namespace fileop {
     std::string filename(std::string path);
     /**
      * @brief Close all open streams
+     * If no function is called, will return 0.
      * @return 0(>=0) succeed. EOF error happened.
     */
     int fcloseall();

utils_config.h.in

@@ -16,3 +16,4 @@
 #cmakedefine HAVE_STRCASECMP @HAVE_STRCASECMP@
 #cmakedefine HAVE__STRNICMP @HAVE__STRNICMP@
 #cmakedefine HAVE_STRNCASECMP @HAVE_STRNCASECMP@
+#cmakedefine HAVE_FCLOSEALL @HAVE_FCLOSEALL@