diff --git a/internal/sys.hpp b/internal/sys.hpp
index fb824ef..9327799 100644
--- a/internal/sys.hpp
+++ b/internal/sys.hpp
@@ -34,6 +34,7 @@
                        off_t offset) const = 0;
     virtual int munmap(void* addr, size_t length) const = 0;
     virtual int getpagesize() const = 0;
+    virtual int ioctl(int fd, unsigned long request, void* param) const = 0;
 };
 
 /**
@@ -50,6 +51,7 @@
                off_t offset) const override;
     int munmap(void* addr, size_t length) const override;
     int getpagesize() const override;
+    int ioctl(int fd, unsigned long request, void* param) const override;
 };
 
 /** @brief Default instantiation of sys */