diff --git a/folly/portability/BUCK b/folly/portability/BUCK
index c7fd0b4bdf2..b191b0c989b 100755
--- a/folly/portability/BUCK
+++ b/folly/portability/BUCK
@@ -295,6 +295,7 @@ cpp_library(
     ],
     exported_deps = [
         ":config",
+        "//folly:c_portability",
     ],
 )
 
@@ -366,6 +367,7 @@ cpp_library(
     ],
     exported_deps = [
         ":sys_types",
+        "//folly:c_portability",
     ],
 )
 
diff --git a/folly/portability/Fcntl.h b/folly/portability/Fcntl.h
index 8b5759f7bd4..eb149e130a4 100644
--- a/folly/portability/Fcntl.h
+++ b/folly/portability/Fcntl.h
@@ -65,3 +65,13 @@ FOLLY_POP_WARNING
 #else
 #define FOLLY_PORT_WIN32_OPEN_BINARY 0
 #endif
+
+namespace folly {
+namespace fileops {
+#ifdef _WIN32
+using portability::fcntl::open;
+#else
+using ::open;
+#endif
+} // namespace fileops
+} // namespace folly
diff --git a/folly/portability/Stdlib.cpp b/folly/portability/Stdlib.cpp
index e77a895efb7..53602dfeaec 100644
--- a/folly/portability/Stdlib.cpp
+++ b/folly/portability/Stdlib.cpp
@@ -26,7 +26,9 @@
 #include <folly/portability/SysStat.h>
 #include <folly/portability/Windows.h>
 
-extern "C" {
+namespace folly {
+namespace portability {
+namespace stdlib {
 char* mktemp(char* tn) {
   return _mktemp(tn);
 }
@@ -138,7 +140,9 @@ int unsetenv(const char* name) {
   }
   return 0;
 }
-}
+} // namespace stdlib
+} // namespace portability
+} // namespace folly
 
 #endif
 
@@ -147,7 +151,7 @@ int unsetenv(const char* name) {
 #include <string>
 #include <vector>
 
-extern "C" int clearenv() {
+int folly::portability::stdlib::clearenv() {
   std::vector<std::string> data;
   for (auto it = environ; it && *it; ++it) {
     std::string entry(*it);
diff --git a/folly/portability/Stdlib.h b/folly/portability/Stdlib.h
index c9d8f97e3ff..acba5d187c3 100644
--- a/folly/portability/Stdlib.h
+++ b/folly/portability/Stdlib.h
@@ -18,6 +18,7 @@
 
 #include <cstdlib>
 
+#include <folly/CPortability.h>
 #include <folly/portability/Config.h>
 
 #if defined(__APPLE__)
@@ -39,12 +40,6 @@ extern "C" {
 #define NAME_MAX _MAX_FNAME
 #define HOST_NAME_MAX 255
 
-char* mktemp(char* tn);
-char* mkdtemp(char* tn);
-int mkstemp(char* tn);
-char* realpath(const char* path, char* resolved_path);
-int setenv(const char* name, const char* value, int overwrite);
-int unsetenv(const char* name);
 #elif defined(__APPLE__)
 // environ doesn't work well with dylibs, so use _NSGetEnviron instead.
 #if !__has_include(<crt_externs.h>)
@@ -57,8 +52,30 @@ char*** _NSGetEnviron(void);
 // Needed to resolve linkage
 extern char** environ;
 #endif
+}
 
+namespace folly {
+namespace portability {
+namespace stdlib {
 #if !__linux__ && !FOLLY_MOBILE
 int clearenv();
 #endif
-}
+
+#ifdef _WIN32
+char* mktemp(char* tn);
+char* mkdtemp(char* tn);
+int mkstemp(char* tn);
+char* realpath(const char* path, char* resolved_path);
+int setenv(const char* name, const char* value, int overwrite);
+int unsetenv(const char* name);
+#endif
+} // namespace stdlib
+} // namespace portability
+} // namespace folly
+
+#if defined(_WIN32) || (!__linux__ && !FOLLY_MOBILE)
+FOLLY_PUSH_WARNING
+FOLLY_CLANG_DISABLE_WARNING("-Wheader-hygiene")
+/* using override */ using namespace folly::portability::stdlib;
+FOLLY_POP_WARNING
+#endif
diff --git a/folly/portability/SysStat.cpp b/folly/portability/SysStat.cpp
index 21441f0560e..5db05f6b5d1 100644
--- a/folly/portability/SysStat.cpp
+++ b/folly/portability/SysStat.cpp
@@ -19,7 +19,9 @@
 #ifdef _WIN32
 #include <folly/portability/Windows.h>
 
-extern "C" {
+namespace folly {
+namespace portability {
+namespace sysstat {
 int chmod(char const* fn, int am) {
   return _chmod(fn, am);
 }
@@ -62,5 +64,7 @@ int mkdir(const char* fn, int /* mode */) {
 int umask(int md) {
   return _umask(md);
 }
-}
+} // namespace sysstat
+} // namespace portability
+} // namespace folly
 #endif
diff --git a/folly/portability/SysStat.h b/folly/portability/SysStat.h
index 88236865109..0a6c0bd2fee 100644
--- a/folly/portability/SysStat.h
+++ b/folly/portability/SysStat.h
@@ -18,6 +18,8 @@
 
 #include <sys/stat.h>
 
+#include <folly/CPortability.h>
+
 #ifdef _WIN32
 #include <folly/portability/SysTypes.h>
 
@@ -42,11 +44,20 @@
 // This isn't defined anywhere, so give a sane value.
 #define MAXSYMLINKS 255
 
-extern "C" {
+namespace folly {
+namespace portability {
+namespace sysstat {
 int chmod(char const* fn, int am);
 int fchmod(int fd, mode_t mode);
 int lstat(const char* path, struct stat* st);
 int mkdir(const char* fn, int mode);
 int umask(int md);
-}
+} // namespace sysstat
+} // namespace portability
+} // namespace folly
+
+FOLLY_PUSH_WARNING
+FOLLY_CLANG_DISABLE_WARNING("-Wheader-hygiene")
+/* using override */ using namespace folly::portability::sysstat;
+FOLLY_POP_WARNING
 #endif
diff --git a/folly/portability/Unistd.h b/folly/portability/Unistd.h
index 1b8dd7484fe..91e664e8c70 100644
--- a/folly/portability/Unistd.h
+++ b/folly/portability/Unistd.h
@@ -109,3 +109,19 @@ FOLLY_CLANG_DISABLE_WARNING("-Wheader-hygiene")
 /* using override */ using namespace folly::portability::unistd;
 FOLLY_POP_WARNING
 #endif
+
+namespace folly {
+namespace fileops {
+#ifdef _WIN32
+using folly::portability::unistd::close;
+using folly::portability::unistd::pipe;
+using folly::portability::unistd::read;
+using folly::portability::unistd::write;
+#else
+using ::close;
+using ::pipe;
+using ::read;
+using ::write;
+#endif
+} // namespace fileops
+} // namespace folly