From 9da33738764e7fb1a6b8d4085804a7f901aa74cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Tue, 26 Jun 2012 18:28:41 +0200
Subject: [PATCH] Fixed #3919 (False positive: uninitialized variable (extern))

---
 lib/checkuninitvar.cpp |  4 ++--
 test/testuninitvar.cpp | 13 +++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/checkuninitvar.cpp b/lib/checkuninitvar.cpp
index bcf4bf141..60f49c4a2 100644
--- a/lib/checkuninitvar.cpp
+++ b/lib/checkuninitvar.cpp
@@ -390,7 +390,7 @@ private:
         // Variable declaration..
         if (tok.varId() && Token::Match(&tok, "%var% [[;]")) {
             const Variable* var2 = symbolDatabase->getVariableFromVarId(tok.varId());
-            if (var2 && var2->nameToken() == &tok && !var2->isStatic() && !var2->isConst()) {
+            if (var2 && var2->nameToken() == &tok && !var2->isStatic() && !var2->isExtern() && !var2->isConst()) {
                 if (tok.linkAt(1)) { // array
                     const Token* endtok = tok.next();
                     while (endtok->link())
@@ -1044,7 +1044,7 @@ void CheckUninitVar::check()
 void CheckUninitVar::checkScope(const Scope* scope)
 {
     for (std::list<Variable>::const_iterator i = scope->varlist.begin(); i != scope->varlist.end(); ++i) {
-        if ((i->type() && !i->isPointer()) || i->isStatic() || i->isConst() || i->isArray() || i->isReference())
+        if ((i->type() && !i->isPointer()) || i->isStatic() || i->isExtern() || i->isConst() || i->isArray() || i->isReference())
             continue;
         if (i->nameToken()->strAt(1) == "(")
             continue;
diff --git a/test/testuninitvar.cpp b/test/testuninitvar.cpp
index b157defe2..fd18f8e3e 100644
--- a/test/testuninitvar.cpp
+++ b/test/testuninitvar.cpp
@@ -207,6 +207,13 @@ private:
                        "}\n");
         ASSERT_EQUALS("[test.cpp:4]: (error) Uninitialized variable: a\n", errout.str());
 
+        checkUninitVar("void f()\n"
+                       "{\n"
+                       "    extern int a;\n"
+                       "    a++;\n"
+                       "}\n");
+        ASSERT_EQUALS("", errout.str());
+
         checkUninitVar("void f()\n"
                        "{\n"
                        "    int a;\n"
@@ -1914,6 +1921,12 @@ private:
                         "}");
         ASSERT_EQUALS("", errout.str());
 
+        checkUninitVar2("int f() {\n"
+                        "    extern int x;\n"
+                        "    return ++x;\n"
+                        "}");
+        ASSERT_EQUALS("", errout.str());
+
         // using uninit var in condition
         checkUninitVar2("void f() {\n"
                         "    int x;\n"