diff --git a/src/os/gnatcoll-os-fsutil-read_symbolic_link__unix.adb b/src/os/gnatcoll-os-fsutil-read_symbolic_link__unix.adb
index a9429327..5e5858cf 100644
--- a/src/os/gnatcoll-os-fsutil-read_symbolic_link__unix.adb
+++ b/src/os/gnatcoll-os-fsutil-read_symbolic_link__unix.adb
@@ -22,6 +22,7 @@
 ------------------------------------------------------------------------------
 
 with Interfaces.C;
+with GNATCOLL.Memory; use GNATCOLL.Memory;
 with GNATCOLL.OS.Libc; use GNATCOLL.OS.Libc;
 with GNATCOLL.String_Builders;
 with Ada.Strings.Unbounded;
@@ -38,13 +39,12 @@ is
    use all type SB.Static_String_Builder;
 
    Link_C_Path : SB.Static_String_Builder (Link_Path'Length + 1);
-   Bytes_Read  : Sint_64;
+   Bytes_Read  : GNATCOLL.Memory.ssize_t;
    C_Buf       : C.char_array (1 .. 4096) := (others => C.nul);
    --  PATH_MAX is usually set to 4096 bytes, so we set the maximum
    --  target path length to this value.
 
 begin
-
    Append (Link_C_Path, Link_Path);
 
    Bytes_Read :=
diff --git a/src/os/unix/gnatcoll-os-libc.ads b/src/os/unix/gnatcoll-os-libc.ads
index 31e1423d..55dbb147 100644
--- a/src/os/unix/gnatcoll-os-libc.ads
+++ b/src/os/unix/gnatcoll-os-libc.ads
@@ -267,8 +267,10 @@ package GNATCOLL.OS.Libc is
      Import => True, Convention => C, External_Name => "symlinkat";
 
    function ReadLink
-     (Path_Name : C_String; Buf : out char_array; Buf_Size : Uint_64)
-      return Sint_64 with
+     (Path_Name : C_String;
+      Buf       : out char_array;
+      Buf_Size  : GNATCOLL.Memory.size_t)
+      return GNATCOLL.Memory.ssize_t with
      Import => True, Convention => C, External_Name => "readlink";
 
 end GNATCOLL.OS.Libc;