diff --git a/src/llama-mmap.cpp b/src/llama-mmap.cpp
index 5be8c8a19..a8cb9439b 100644
--- a/src/llama-mmap.cpp
+++ b/src/llama-mmap.cpp
@@ -244,9 +244,13 @@ size_t llama_file::size() const { return pimpl->size; }
 int llama_file::file_id() const {
 #ifdef _WIN32
     return _fileno(pimpl->fp);
+#else
+#if defined(fileno)
+    return fileno(pimpl->fp);
 #else
     return ::fileno(pimpl->fp);
 #endif
+#endif
 }
 
 void llama_file::seek(size_t offset, int whence) const { pimpl->seek(offset, whence); }