diff --git a/CMakeLists.txt b/CMakeLists.txt
index eee1630..ca01c01 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -95,6 +95,8 @@ if (NOT MSVC)
 endif()
 if (NOT WIN32)
     check_symbol_exists(clock_gettime "time.h" HAVE_CLOCK_GETTIME)
+    check_symbol_exists(usleep "unistd.h" HAVE_USLEEP)
+    check_symbol_exists(nanosleep "time.h" HAVE_NANOSLEEP)
 endif()
 configure_file("${CMAKE_CURRENT_SOURCE_DIR}/utils_config.h.in" "${CMAKE_CURRENT_BINARY_DIR}/utils_config.h")
 
diff --git a/cfileop.h b/cfileop.h
index 3435614..6708345 100644
--- a/cfileop.h
+++ b/cfileop.h
@@ -11,6 +11,8 @@ extern "C" {
 #include <fcntl.h>
 #if _WIN32
 #include <io.h>
+#else
+#include <unistd.h>
 #endif
 /**
  * @brief Check file exists
diff --git a/http_client.h b/http_client.h
index 1685579..74ef7e2 100644
--- a/http_client.h
+++ b/http_client.h
@@ -8,6 +8,7 @@
 #include <map>
 #include <memory>
 #include <vector>
+#include <string.h>
 #include "cstr_util.h"
 #include "utils_config.h"
 
diff --git a/time_util.cpp b/time_util.cpp
index b6e41bc..9f10c26 100644
--- a/time_util.cpp
+++ b/time_util.cpp
@@ -17,6 +17,10 @@
 
 #include "err.h"
 
+#if HAVE_USLEEP
+#include <unistd.h>
+#endif
+
 #if _WIN32
 void time_util::time_t_to_file_time(time_t t, LPFILETIME pft) {
     ULARGE_INTEGER time_value;
@@ -64,11 +68,11 @@ time_t time_util::timegm(struct tm* tm) {
 #endif
 }
 
-time_t time_util::time_ns() {
+size_t time_util::time_ns() {
 #if _WIN32
     FILETIME ft;
     GetSystemTimeAsFileTime(&ft);
-    time_t t = ((size_t)ft.dwHighDateTime << 32) | (size_t)ft.dwLowDateTime;
+    size_t t = ((size_t)ft.dwHighDateTime << 32) | (size_t)ft.dwLowDateTime;
     return t;
 #elif HAVE_CLOCK_GETTIME
     struct timespec ts;
@@ -78,3 +82,28 @@ time_t time_util::time_ns() {
     return time(NULL) * 1000000000LL;
 #endif
 }
+
+size_t time_time_ns() {
+    return time_util::time_ns();
+}
+
+int time_util::mssleep(unsigned int ms) {
+#if _WIN32
+    Sleep(ms);
+    return 0;
+#elif HAVE_USLEEP
+    return usleep(ms);
+#elif HAVE_NANOSLEEP
+    struct timespec ts;
+    ts.tv_sec = ms / 1000;
+    ts.tv_nsec = (ms % 1000) * 1000000;
+    return nanosleep(&ts, NULL);
+#else
+    printf("mssleep failed: not implemented\n");
+    return -1;
+#endif
+}
+
+int mssleep(unsigned int ms) {
+    return time_util::mssleep(ms);
+}
diff --git a/time_util.h b/time_util.h
index dfc5193..541ec30 100644
--- a/time_util.h
+++ b/time_util.h
@@ -5,6 +5,8 @@
 #include <Windows.h>
 #endif
 
+#if __cplusplus
+
 namespace time_util {
 #if _WIN32
     /**
@@ -17,6 +19,18 @@ namespace time_util {
     char* strptime(const char* s, const char* format, struct tm* tm);
     long get_timezone();
     time_t timegm(struct tm* tm);
-    time_t time_ns();
+    size_t time_ns();
+    int mssleep(unsigned int ms);
+}
+
+extern "C" {
+#endif
+
+size_t time_time_ns();
+int mssleep(unsigned int ms);
+
+#if __cplusplus
 }
 #endif
+
+#endif
diff --git a/utils_config.h.in b/utils_config.h.in
index a29b5b9..25b207c 100644
--- a/utils_config.h.in
+++ b/utils_config.h.in
@@ -27,3 +27,5 @@
 #cmakedefine HAVE_TZSET @HAVE_TZSET@
 #cmakedefine HAVE_FPRINTF_S @HAVE_FPRINTF_S@
 #cmakedefine HAVE_CLOCK_GETTIME @HAVE_CLOCK_GETTIME@
+#cmakedefine HAVE_USLEEP @HAVE_USLEEP@
+#cmakedefine HAVE_NANOSLEEP @HAVE_NANOSLEEP@