fix io and fs compile on mac

test=develop

paddle/fluid/framework/io/shell.cc

@@ -19,7 +19,9 @@ namespace framework {
 
 std::shared_ptr<FILE> shell_fopen(const std::string& path,
                                   const std::string& mode) {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return nullptr;
+#else
   if (shell_verbose()) {
     LOG(INFO) << "Opening file[" << path << "] with mode[" << mode << "]";
   }
@@ -35,8 +37,6 @@ std::shared_ptr<FILE> shell_fopen(const std::string& path,
               LOG(FATAL) << "fclose fail, path[" << path << "]";
             }
           }};
-#else
-  return nullptr;
 #endif
 }
 
@@ -44,7 +44,9 @@ std::shared_ptr<FILE> shell_fopen(const std::string& path,
 // The implementation is async signal safe
 // Mostly copy from CPython code
 static int close_open_fds_internal() {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return 0;
+#else
   struct linux_dirent {
     long d_ino = 0;  // NOLINT
     off_t d_off;
@@ -91,13 +93,15 @@ static int close_open_fds_internal() {
   }
 
   close(dir_fd);
-#endif
   return 0;
+#endif
 }
 
 static int shell_popen_fork_internal(const char* real_cmd, bool do_read,
                                      int parent_end, int child_end) {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return 0;
+#else
   int child_pid = -1;
   // Too frequent calls to fork() makes openmpi very slow. Use vfork() instead.
   // But vfork() is very dangerous. Be careful.
@@ -127,12 +131,13 @@ static int shell_popen_fork_internal(const char* real_cmd, bool do_read,
   }
   exit(127);
 #endif
-  return 0;
 }
 
 std::shared_ptr<FILE> shell_popen(const std::string& cmd,
                                   const std::string& mode, int* err_no) {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return nullptr;
+#else
   bool do_read = mode == "r";
   bool do_write = mode == "w";
   if (!(do_read || do_write)) {
@@ -197,7 +202,9 @@ std::shared_ptr<FILE> shell_popen(const std::string& cmd,
 
 static int shell_p2open_fork_internal(const char* real_cmd, int pipein_fds[2],
                                       int pipeout_fds[2]) {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return 0;
+#else
   int child_pid = -1;
   if ((child_pid = fork()) < 0) {
     return -1;
@@ -230,12 +237,13 @@ static int shell_p2open_fork_internal(const char* real_cmd, int pipein_fds[2],
   }
   exit(127);
 #endif
-  return 0;
 }
 
 std::pair<std::shared_ptr<FILE>, std::shared_ptr<FILE>> shell_p2open(
     const std::string& cmd) {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return nullptr;
+#else
   if (shell_verbose()) {
     LOG(INFO) << "Opening bidirectional pipe[" << cmd << "]";
   }
@@ -287,13 +295,13 @@ std::pair<std::shared_ptr<FILE>, std::shared_ptr<FILE>> shell_p2open(
   PCHECK((out_fp = fdopen(pipeout_fds[1], "w")) != NULL);
   return {{in_fp, [child_life](FILE* fp) { PCHECK(fclose(fp) == 0); }},
           {out_fp, [child_life](FILE* fp) { PCHECK(fclose(fp) == 0); }}};
-#else
-  return nullptr;
 #endif
 }
 
 std::string shell_get_command_output(const std::string& cmd) {
-#ifndef _WIN32
+#if defined _WIN32 || defined __APPLE__
+  return "";
+#else
   int err_no = 0;
   do {
     err_no = 0;
@@ -308,7 +316,6 @@ std::string shell_get_command_output(const std::string& cmd) {
     }
   } while (err_no == -1);
 #endif
-  return "";
 }
 }  // end namespace framework
 }  // end namespace paddle