diff --git a/src/libimp/platform/posix/system.h b/src/libimp/platform/posix/system.h
index 57396a9..1529643 100644
--- a/src/libimp/platform/posix/system.h
+++ b/src/libimp/platform/posix/system.h
@@ -4,10 +4,6 @@
  */
 #pragma once
 
-#include <exception>
-#include <memory>
-#include <type_traits>
-
 #include <errno.h>
 #include <string.h>
 
@@ -40,7 +36,13 @@ void error_code(result_code code) noexcept {
  * https://man7.org/linux/man-pages/man3/strerror_l.3.html
  */
 std::string error_msg(result_code code) noexcept {
-  return {};
+  LIBIMP_LOG_();
+  char msg_buf[256] {};
+  if (::strerror_r((int)code.value(), msg_buf, sizeof(msg_buf)) != 0) {
+    log.error("strerror_r fails. return = {}", error_code());
+    return {};
+  }
+  return msg_buf;
 }
 
 } // namespace sys
diff --git a/src/libimp/platform/win/system.h b/src/libimp/platform/win/system.h
index be23f92..5820e03 100644
--- a/src/libimp/platform/win/system.h
+++ b/src/libimp/platform/win/system.h
@@ -44,7 +44,7 @@ void error_code(result_code code) noexcept {
 std::string error_msg(result_code code) noexcept {
   LIBIMP_LOG_();
   try {
-    DWORD err = code ? ERROR_SUCCESS : (DWORD)code.value();
+    DWORD err = (DWORD)code.value();
     LPTSTR lpErrText = NULL;
     if (::FormatMessage(
           FORMAT_MESSAGE_ALLOCATE_BUFFER | 
diff --git a/test/test_imp_system.cpp b/test/test_imp_system.cpp
index e6e9f93..c64592f 100644
--- a/test/test_imp_system.cpp
+++ b/test/test_imp_system.cpp
@@ -52,5 +52,6 @@ TEST(system, error_msg) {
     EXPECT_EQ(imp::sys::error_msg({false, ERROR_INVALID_HANDLE}), s_txt);
   }
 #else
+  imp::sys::error_msg({false, 1234}, "Unknown error nnn");
 #endif
 }
\ No newline at end of file