diff --git a/libmaxsi/decl/errno_values.h b/libmaxsi/decl/errno_values.h
index 4e435ff2..783051be 100644
--- a/libmaxsi/decl/errno_values.h
+++ b/libmaxsi/decl/errno_values.h
@@ -22,5 +22,6 @@
 #define ESRCH 30
 #define ENOTTY 31
 #define ECHILD 32
+#define ENOSYS 33
 
 #endif
diff --git a/libmaxsi/error.cpp b/libmaxsi/error.cpp
index a48ab409..9ebede16 100644
--- a/libmaxsi/error.cpp
+++ b/libmaxsi/error.cpp
@@ -70,6 +70,7 @@ namespace Maxsi
 				case ESRCH: return (char*) "No such process";
 				case ENOTTY: return (char*) "Not a tty";
 				case ECHILD: return (char*) "No child processes";
+				case ENOSYS: return (char*) "Function not implemented";
 				default: return (char*) "Unknown error condition";
 			}
 		}