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// Copyright 2010, Niels Dekker.
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Test program for the boost::value_initialized<T> workaround.
//
// 17 June 2010 (Created) Niels Dekker
// Switch the workaround off, before inluding "value_init.hpp".
#define BOOST_DETAIL_VALUE_INIT_WORKAROUND 0
#include <boost/utility/value_init.hpp>
#include <iostream> // For cout.
#include <cstdlib> // For EXIT_SUCCESS and EXIT_FAILURE.
namespace
{
struct empty_struct
{
};
// A POD aggregate struct derived from an empty struct.
// Similar to struct Foo1 from Microsoft Visual C++ bug report 484295,
// "VC++ does not value-initialize members of derived classes without
// user-declared constructor", reported in 2009 by Sylvester Hesp:
// https://connect.microsoft.com/VisualStudio/feedback/details/484295
struct derived_struct: empty_struct
{
int data;
};
bool is_value_initialized(const derived_struct& arg)
{
return arg.data == 0;
}
class virtual_destructor_holder
{
public:
int i;
virtual ~virtual_destructor_holder()
{
}
};
bool is_value_initialized(const virtual_destructor_holder& arg)
{
return arg.i == 0;
}
// Equivalent to the Stats class from GCC Bug 33916,
// "Default constructor fails to initialize array members", reported in 2007 by
// Michael Elizabeth Chastain: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33916
// and fixed for GCC 4.2.4.
class private_int_array_pair
{
friend bool is_value_initialized(const private_int_array_pair& arg);
private:
int first[12];
int second[12];
};
bool is_value_initialized(const private_int_array_pair& arg)
{
for ( unsigned i = 0; i < 12; ++i)
{
if ( (arg.first[i] != 0) || (arg.second[i] != 0) )
{
return false;
}
}
return true;
}
template <typename T>
bool is_value_initialized(const T(& arg)[2])
{
return
is_value_initialized(arg[0]) &&
is_value_initialized(arg[1]);
}
template <typename T>
bool is_value_initialized(const boost::value_initialized<T>& arg)
{
return is_value_initialized(arg.data());
}
// Returns zero when the specified object is value-initializated, and one otherwise.
// Prints a message to standard output if the value-initialization has failed.
template <class T>
unsigned failed_to_value_initialized(const T& object, const char *const object_name)
{
if ( is_value_initialized(object) )
{
return 0u;
}
else
{
std::cout << "Note: Failed to value-initialize " << object_name << '.' << std::endl;
return 1u;
}
}
// A macro that passed both the name and the value of the specified object to
// the function above here.
#define FAILED_TO_VALUE_INITIALIZE(value) failed_to_value_initialized(value, #value)
// Equivalent to the dirty_stack() function from GCC Bug 33916,
// "Default constructor fails to initialize array members", reported in 2007 by
// Michael Elizabeth Chastain: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33916
void dirty_stack()
{
unsigned char array_on_stack[4096];
for (unsigned i = 0; i < sizeof(array_on_stack); ++i)
{
array_on_stack[i] = 0x11;
}
}
}
int main()
{
dirty_stack();
// TODO More types may be added later.
const unsigned num_failures =
FAILED_TO_VALUE_INITIALIZE(boost::value_initialized<derived_struct>()) +
FAILED_TO_VALUE_INITIALIZE(boost::value_initialized<virtual_destructor_holder[2]>()) +
FAILED_TO_VALUE_INITIALIZE(boost::value_initialized<private_int_array_pair>());
#ifdef BOOST_DETAIL_VALUE_INIT_WORKAROUND_SUGGESTED
// One or more failures are expected.
return num_failures > 0 ? EXIT_SUCCESS : EXIT_FAILURE;
#else
// No failures are expected.
return num_failures == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
#endif
}
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