diff --git a/libc/decl/errno_values.h b/libc/decl/errno_values.h
index ecf71313..fbadf28b 100644
--- a/libc/decl/errno_values.h
+++ b/libc/decl/errno_values.h
@@ -73,6 +73,7 @@
 #define EDEADLK 81
 #define ENFILE 82
 #define EPROTOTYPE 83
+#define ENOLCK 84
 
 #define EOPNOTSUPP ENOTSUP
 
diff --git a/libc/strerror.cpp b/libc/strerror.cpp
index d718e7a0..bbbfae05 100644
--- a/libc/strerror.cpp
+++ b/libc/strerror.cpp
@@ -102,6 +102,7 @@ extern "C" const char* sortix_strerror(int errnum)
 	case EDEADLK: return "Resource deadlock avoided";
 	case ENFILE: return "Too many open files in system";
 	case EPROTOTYPE: return "Wrong protocol type for socket";
+	case ENOLCK: return "No locks available";
 	default: return "Unknown error condition";
 	}
 }