From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 6 Nov 2009 09:39:13 +0000 (+0100)
Subject: Add sentinel attribute for NULL terminated arg lists
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=649bcd72fec9f93253201126f498982028c487c0;p=libvirt.git

Add sentinel attribute for NULL terminated arg lists

* src/internal.h (ATTRIBUTE_SENTINEL): New, it's a ggc feature and
  protected as such
* src/util/buf.c (virBufferStrcat): Use it.
* src/util/ebtables.c (ebtablesAddRemoveRule): Use it.
* src/util/iptables.c (iptableAddRemoveRule: Use it.
* src/util/qparams.h (new_qparam_set, append_qparams): Use it.
* docs/apibuild.py: avoid breaking the API generator with that new
  internal keyword macro
---

diff --git a/docs/apibuild.py b/docs/apibuild.py
index c5257f3813..e233c8b43b 100755
--- a/docs/apibuild.py
+++ b/docs/apibuild.py
@@ -26,6 +26,7 @@ included_files = {
 
 ignored_words = {
   "ATTRIBUTE_UNUSED": (0, "macro keyword"),
+  "ATTRIBUTE_SENTINEL": (0, "macro keyword"),
   "VIR_DEPRECATED": (0, "macro keyword"),
   "WINAPI": (0, "Windows keyword"),
   "__declspec": (3, "Windows keyword"),
diff --git a/src/internal.h b/src/internal.h
index bd1cfe680b..09c19eae6a 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -92,6 +92,17 @@
 #define ATTRIBUTE_UNUSED __attribute__((__unused__))
 #endif
 
+/**
+ * ATTRIBUTE_SENTINEL:
+ *
+ * Macro to check for NULL-terminated varargs lists
+ */
+#ifndef ATTRIBUTE_SENTINEL
+#if __GNUC_PREREQ (4, 0)
+#define ATTRIBUTE_SENTINEL __attribute__((__sentinel__))
+#endif
+#endif
+
 /**
  * ATTRIBUTE_FMT_PRINTF
  *
diff --git a/src/util/buf.h b/src/util/buf.h
index 7d31cb2ac2..94ee8a3d10 100644
--- a/src/util/buf.h
+++ b/src/util/buf.h
@@ -41,7 +41,8 @@ void virBufferAdd(const virBufferPtr buf, const char *str, int len);
 void virBufferAddChar(const virBufferPtr buf, char c);
 void virBufferVSprintf(const virBufferPtr buf, const char *format, ...)
   ATTRIBUTE_FMT_PRINTF(2, 3);
-void virBufferStrcat(const virBufferPtr buf, ...);
+void virBufferStrcat(const virBufferPtr buf, ...)
+  ATTRIBUTE_SENTINEL;
 void virBufferEscapeString(const virBufferPtr buf, const char *format, const char *str);
 void virBufferURIEncodeString (const virBufferPtr buf, const char *str);
 
diff --git a/src/util/ebtables.c b/src/util/ebtables.c
index 60427d7099..20f33425be 100644
--- a/src/util/ebtables.c
+++ b/src/util/ebtables.c
@@ -175,7 +175,7 @@ ebtRulesNew(const char *table,
     return NULL;
 }
 
-static int
+static int ATTRIBUTE_SENTINEL
 ebtablesAddRemoveRule(ebtRules *rules, int action, const char *arg, ...)
 {
     va_list args;
diff --git a/src/util/iptables.c b/src/util/iptables.c
index 45628009ce..284f3c0f02 100644
--- a/src/util/iptables.c
+++ b/src/util/iptables.c
@@ -382,7 +382,7 @@ iptRulesNew(const char *table,
     return NULL;
 }
 
-static int
+static int ATTRIBUTE_SENTINEL
 iptablesAddRemoveRule(iptRules *rules, int action, const char *arg, ...)
 {
     va_list args;
diff --git a/src/util/qparams.h b/src/util/qparams.h
index 1a92048196..a2f5aa2e1a 100644
--- a/src/util/qparams.h
+++ b/src/util/qparams.h
@@ -38,10 +38,12 @@ struct qparam_set {
 };
 
 /* New parameter set. */
-extern struct qparam_set *new_qparam_set (int init_alloc, ...);
+extern struct qparam_set *new_qparam_set (int init_alloc, ...)
+    ATTRIBUTE_SENTINEL;
 
 /* Appending parameters. */
-extern int append_qparams (struct qparam_set *ps, ...);
+extern int append_qparams (struct qparam_set *ps, ...)
+    ATTRIBUTE_SENTINEL;
 extern int append_qparam (struct qparam_set *ps,
                           const char *name, const char *value);