Add `scm_immutable_cell ()'.

[bpt/guile.git] / libguile / inline.h

diff --git a/libguile/inline.h b/libguile/inline.h
index 3fae97c..3a4302a 100644 (file)
--- a/libguile/inline.h
+++ b/libguile/inline.h
@@ -80,6 +80,7 @@
 
 
 SCM_API SCM scm_cell (scm_t_bits car, scm_t_bits cdr);
+SCM_API SCM scm_immutable_cell (scm_t_bits car, scm_t_bits cdr);
 SCM_API SCM scm_double_cell (scm_t_bits car, scm_t_bits cbr,
                             scm_t_bits ccr, scm_t_bits cdr);
 
@@ -124,6 +125,26 @@ scm_cell (scm_t_bits car, scm_t_bits cdr)
   return cell;
 }
 
+#ifndef SCM_INLINE_C_INCLUDING_INLINE_H
+SCM_C_EXTERN_INLINE
+#endif
+SCM
+scm_immutable_cell (scm_t_bits car, scm_t_bits cdr)
+{
+  SCM cell = SCM_PACK ((scm_t_bits) (GC_MALLOC_STUBBORN (sizeof (scm_t_cell))));
+
+  /* Initialize the type slot last so that the cell is ignored by the GC
+     until it is completely initialized.  This is only relevant when the GC
+     can actually run during this code, which it can't since the GC only runs
+     when all other threads are stopped.  */
+  SCM_GC_SET_CELL_WORD (cell, 1, cdr);
+  SCM_GC_SET_CELL_WORD (cell, 0, car);
+
+  GC_END_STUBBORN_CHANGE ((void *) cell);
+
+  return cell;
+}
+
 #ifndef SCM_INLINE_C_INCLUDING_INLINE_H
 SCM_C_EXTERN_INLINE
 #endif