diff --git a/src/doc/unix-transactional.h.0.md b/src/doc/unix-transactional.h.0.md
index b48d1c9..e0afbe3 100644
--- a/src/doc/unix-transactional.h.0.md
+++ b/src/doc/unix-transactional.h.0.md
@@ -22,6 +22,12 @@ operations.
 
 The following functions are defined :
 
+: [openb_readat](3)
+:: Same as [openb_read](3) but relative path are based on given file descriptor.
+
+: [openbc_readat](3)
+:: Same as [openc_read](3) but relative path are based on given file descriptor.
+
 : [open_createat](3)
 :: Same as [open_create](3) but relative path are based of given file descriptor
 
diff --git a/src/doc/unix-transactional.h/openb_readat.3.md b/src/doc/unix-transactional.h/openb_readat.3.md
new file mode 100644
index 0000000..3cd837d
--- /dev/null
+++ b/src/doc/unix-transactional.h/openb_readat.3.md
@@ -0,0 +1,35 @@
+% limb manual
+% openb_readat(3)
+
+# NAME
+
+openb\_readat, openbc\_readat - open file relative to directory file descriptor
+
+# SYNOPSIS
+
+    #include <limb/unix-transactional.h>
+
+```pre hl
+int openb_readat(int <em>fd</em>, const char *<em>file</em>);
+int openbc_readat(int <em>fd</em>, const char *<em>file</em>);
+```
+
+# DESCRIPTION
+
+The `openb_readat`() function opens `file` for reading in blocking mode. If
+`file` specifies a relative path, it is relative to the directory associated
+with the file descripor `fd`, which may be *AT_FDCWD* to use the current working
+directory.
+
+The `openbc_readat`() function is similar, only with the *FD_CLOEXEC* flag set
+for the opened file descriptor.
+
+# RETURN VALUE
+
+These functions return the opened file descriptor on success. Otherwise they
+return -1 and set `errno` to indicate the error.
+
+# ERRORS
+
+These functions may fail and set `errno` for any of the errors described for
+[open2_at](3).
diff --git a/src/liblimb/include/limb/unix-transactional.h b/src/liblimb/include/limb/unix-transactional.h
index 736dc96..5fff355 100644
--- a/src/liblimb/include/limb/unix-transactional.h
+++ b/src/liblimb/include/limb/unix-transactional.h
@@ -6,6 +6,9 @@
 
 #include <skalibs/unix-transactional.h>
 
+extern int openb_readat(int fd, const char *file);
+extern int openbc_readat(int fd, const char *file);
+
 extern int openc_createat(int fd, const char *file);
 extern int open_createat(int fd, const char *file);
 extern int openc_exclat(int fd, const char *file);
diff --git a/src/liblimb/unix-transactional.h/openb_readat.c b/src/liblimb/unix-transactional.h/openb_readat.c
new file mode 100644
index 0000000..a1fca88
--- /dev/null
+++ b/src/liblimb/unix-transactional.h/openb_readat.c
@@ -0,0 +1,11 @@
+/* This file is part of limb                           https://lila.oss/limb
+ * Copyright (C) 2023 Olivier Brunel                          jjk@jjacky.com */
+/* SPDX-License-Identifier: GPL-2.0-only */
+#include <fcntl.h>
+#include <limb/unix-transactional.h>
+
+int
+openb_readat(int fd, const char *file)
+{
+    return open2_at(fd, file, O_RDONLY);
+}
diff --git a/src/liblimb/unix-transactional.h/openbc_readat.c b/src/liblimb/unix-transactional.h/openbc_readat.c
new file mode 100644
index 0000000..4305316
--- /dev/null
+++ b/src/liblimb/unix-transactional.h/openbc_readat.c
@@ -0,0 +1,11 @@
+/* This file is part of limb                           https://lila.oss/limb
+ * Copyright (C) 2023 Olivier Brunel                          jjk@jjacky.com */
+/* SPDX-License-Identifier: GPL-2.0-only */
+#include <fcntl.h>
+#include <limb/unix-transactional.h>
+
+int
+openbc_readat(int fd, const char *file)
+{
+    return open2_at(fd, file, O_RDONLY | O_CLOEXEC);
+}