[Boost-users] [PATCH]: filesystem: Shadow Variables Cause Warnings/Errors When Headers Are Not in System Path

From: Grant Erickson (gerickson_at_[hidden])
Date: 2008-07-30 20:11:37

In working through cross-compilation issues with boost, particularly the
filesystem library, I discovered the following error reproduced with the
following test case with both boost 1.34.1 and 1.35.0:

    FAILS:
        echo "#include <boost/filesystem.hpp>\nint main (void) { return (0);
}" | g++ -o test -I/${BuildRoot}/results/boost/include -Werror -Wall
-Wshadow -x c++ -
    
    PASSES:
        echo "#include <boost/filesystem.hpp>\nint main (void) { return (0);
}" | g++ -o test -I/usr/include -Werror -Wall -Wshadow -x c++ -

The failing case complains about 'what', 'path1' and 'path2' argument
shadowing in boost/filesystem/path.hpp with respect to like-named member
functions.

Since GCC does not enforce warning options on headers in /usr/include, this
only shows up when building against a boost installation outside
/usr/include, as in the above failure example.

The patch to address this is:

Signed-off-by: Grant Erickson <gerickson_at_[hidden]>
---
--- boost_1_35_0/boost/filesystem/path.hpp    2008-07-30 16:54:53.000000000
-0700
+++ boost_1_35_0/boost/filesystem/path.hpp.N    2008-07-30
16:59:42.000000000 -0700
@@ -577,23 +577,23 @@
       // BOOST_FILESYSTEM_DECL version works for VC++ but not GCC. Go
figure!
       inline
       const char * what( const char * sys_err_what,
-        const path & path1, const path & path2, std::string & target )
+        const path & path1_arg, const path & path2_arg, std::string &
target )
       {
         try
         {
           if ( target.empty() )
           {
             target = sys_err_what;
-            if ( !path1.empty() )
+            if ( !path1_arg.empty() )
             {
               target += ": \"";
-              target += path1.file_string();
+              target += path1_arg.file_string();
               target += "\"";
             }
-            if ( !path2.empty() )
+            if ( !path2_arg.empty() )
             {
               target += ", \"";
-              target += path2.file_string();
+              target += path2_arg.file_string();
               target += "\"";
             }
           }
@@ -607,7 +607,7 @@
 
       template<class Path>
       const char * what( const char * sys_err_what,
-        const Path & /*path1*/, const Path & /*path2*/, std::string &
/*target*/ )
+        const Path & /*path1_arg*/, const Path & /*path2_arg*/, std::string
& /*target*/ )
       {
         return sys_err_what;
       }
@@ -624,14 +624,14 @@
 
       typedef Path path_type;
 
-      basic_filesystem_error( const std::string & what,
+      basic_filesystem_error( const std::string & what_arg,
         system::error_code ec );
 
-      basic_filesystem_error( const std::string & what,
-        const path_type & path1, system::error_code ec );
+      basic_filesystem_error( const std::string & what_arg,
+        const path_type & path1_arg, system::error_code ec );
 
-      basic_filesystem_error( const std::string & what, const path_type &
path1,
-        const path_type & path2, system::error_code ec );
+      basic_filesystem_error( const std::string & what_arg, const path_type
& path1_arg,
+        const path_type & path2_arg, system::error_code ec );
 
       ~basic_filesystem_error() throw() {}
 
@@ -1385,8 +1385,8 @@
 
     template<class Path>
     basic_filesystem_error<Path>::basic_filesystem_error(
-      const std::string & what, system::error_code ec )
-      : system::system_error(ec, what)
+      const std::string & what_arg, system::error_code ec )
+      : system::system_error(ec, what_arg)
     {
       try
       {
@@ -1397,29 +1397,29 @@
 
     template<class Path>
     basic_filesystem_error<Path>::basic_filesystem_error(
-      const std::string & what, const path_type & path1,
+      const std::string & what_arg, const path_type & path1_arg,
       system::error_code ec )
-      : system::system_error(ec, what)
+      : system::system_error(ec, what_arg)
     {
       try
       {
         m_imp_ptr.reset( new m_imp );
-        m_imp_ptr->m_path1 = path1;
+        m_imp_ptr->m_path1 = path1_arg;
       }
       catch (...) { m_imp_ptr.reset(); }
     }
 
     template<class Path>
     basic_filesystem_error<Path>::basic_filesystem_error(
-      const std::string & what, const path_type & path1,
-      const path_type & path2, system::error_code ec )
-      : system::system_error(ec, what)
+      const std::string & what_arg, const path_type & path1_arg,
+      const path_type & path2_arg, system::error_code ec )
+      : system::system_error(ec, what_arg)
     {
       try
       {
         m_imp_ptr.reset( new m_imp );
-        m_imp_ptr->m_path1 = path1;
-        m_imp_ptr->m_path2 = path2;
+        m_imp_ptr->m_path1 = path1_arg;
+        m_imp_ptr->m_path2 = path2_arg;
       }
       catch (...) { m_imp_ptr.reset(); }
     }
---