From a61b2054b47d20bcc3197feee7756e4033423c21 Mon Sep 17 00:00:00 2001
From: Neil Jerram <neil@ossau.uklinux.net>
Date: Sun, 24 Apr 2005 12:23:24 +0000
Subject: [PATCH] Critical section review

---
 libguile/gh.h        | 2 +-
 libguile/guardians.c | 7 ++++++-
 libguile/keywords.c  | 3 ++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/libguile/gh.h b/libguile/gh.h
index f891f0938..cc230cfa0 100644
--- a/libguile/gh.h
+++ b/libguile/gh.h
@@ -231,7 +231,7 @@ SCM_API void gh_newline (void);
 #endif
 
 #endif /* __GH_H */
-/* njrev: critical sections reviewed so far up to here */
+
 /*
   Local Variables:
   c-file-style: "gnu"
diff --git a/libguile/guardians.c b/libguile/guardians.c
index 5ea384903..f234bac2e 100644
--- a/libguile/guardians.c
+++ b/libguile/guardians.c
@@ -226,6 +226,7 @@ scm_guard (SCM guardian, SCM obj, int throw_p)
       SCM z;
 
       /* This critical section barrier will be replaced by a mutex. */
+      /* njrev: per comment above, should use a mutex. */
       SCM_CRITICAL_SECTION_START;
 
       if (GREEDY_P (g))
@@ -245,6 +246,7 @@ scm_guard (SCM guardian, SCM obj, int throw_p)
           else
             scm_hashq_create_handle_x (greedily_guarded_whash,
                                        obj, guardian);
+	  /* njrev: this can throw a memory or out-of-range error. */
         }
 
       z = scm_cons (SCM_BOOL_F, SCM_BOOL_F);
@@ -265,6 +267,7 @@ scm_get_one_zombie (SCM guardian)
 
   /* This critical section barrier will be replaced by a mutex. */
   SCM_CRITICAL_SECTION_START;
+  /* njrev: -> mutex */
 
   if (!TCONC_EMPTYP (g->zombies))
     TCONC_OUT (g->zombies, res);
@@ -339,7 +342,9 @@ SCM_DEFINE (scm_guardian_destroyed_p, "guardian-destroyed?", 1, 0, 0,
 
   /* This critical section barrier will be replaced by a mutex. */
   SCM_CRITICAL_SECTION_START;
-
+  /* njrev: Critical section not needed here.  (Falls into category of
+     stuff that is the responsibility of Scheme code, whenever
+     accessing data from multiple threads.) */
   res = scm_from_bool (DESTROYED_P (GUARDIAN_DATA (guardian)));
   
   SCM_CRITICAL_SECTION_END;
diff --git a/libguile/keywords.c b/libguile/keywords.c
index 17da78c82..11e7d2e5d 100644
--- a/libguile/keywords.c
+++ b/libguile/keywords.c
@@ -66,6 +66,7 @@ SCM_DEFINE (scm_symbol_to_keyword, "symbol->keyword", 1, 0, 0,
   SCM_ASSERT_TYPE (scm_is_symbol (symbol), symbol, 0, NULL, "symbol");
 
   SCM_CRITICAL_SECTION_START;
+  /* njrev: NEWSMOB and hashq_set_x can raise errors */
   keyword = scm_hashq_ref (scm_keyword_obarray, symbol, SCM_BOOL_F);
   if (scm_is_false (keyword))
     {
@@ -105,7 +106,7 @@ scm_from_locale_keywordn (const char *str, size_t len)
   return scm_symbol_to_keyword (scm_from_locale_symboln (str, len));
 }
 
-
+/* njrev: critical sections reviewed so far up to here */
 void
 scm_init_keywords ()
 {