diff --git a/iceoryx_posh/source/roudi/roudi.cpp b/iceoryx_posh/source/roudi/roudi.cpp
index d0b9134737..2e41ee1245 100644
--- a/iceoryx_posh/source/roudi/roudi.cpp
+++ b/iceoryx_posh/source/roudi/roudi.cpp
@@ -607,9 +607,10 @@ std::string ServiceManagementSystemd::getEnvironmentVariable(const char* const e
 
     str.unsafe_raw_access([&](auto* buffer, auto const info) {
         size_t actualSizeWithNull{0};
-        auto result = IOX_POSIX_CALL(iox_getenv_s)(&actualSizeWithNull, buffer, info.total_size, env_var)
-                          .failureReturnValue(-1)
-                          .evaluate();
+        auto result =
+            IOX_POSIX_CALL(iox_getenv_s)(&actualSizeWithNull, buffer, static_cast<size_t>(info.total_size), env_var)
+                .failureReturnValue(-1)
+                .evaluate();
 
         if (result.has_error() && result.error().errnum == ERANGE)
         {