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Portability Hints: Borland C++ 5.5.1

This page gives portability hints on some language features of the Borland C++ version 5.5.1 compiler. Furthermore, the appendix presents additional problems with Borland C++ version 5.5. Borland C++ 5.5.1 is a freely available command-line compiler for Win32 available at http://www.borland.com/.

Each entry in the following list describes a particular issue, complete with sample source code to demonstrate the effect. Most sample code herein has been verified to compile with gcc 2.95.2 and Comeau C++ 4.2.44.

Preprocessor symbol

Compiler	__BORLANDC__ value
Borland C++ Builder 4	0x0540
Borland C++ Builder 5	0x0550
Borland C++ 5.5	0x0550
Borland C++ 5.5.1	0x0551
Borland C++ Builder 6	0x0560

Core Language

[using-directive] Mixing using-declarations and using-directives

namespace N {
  int x();
}

using N::x;
using namespace N;

int main()
{
  &x;     // Ambiguous overload
}

[using template] using-declarations for class templates

template<class T>
class X { };

namespace N
{
  // "cannot use template 'X<T>' without specifying specialization parameters"
  using ::X;
};

[template const arg] Deduction of constant arguments to function templates

template<class T>
void f(T x)
{
        x = 1;  // works
        (void) &x;
        T y = 17;
        y = 20;  // "Cannot modify a const object in function f<const int>(int)"
        (void) &y;
}

int main()
{
        const int i = 17;
        f(i);
}

[function address] Resolving addresses of overloaded functions

template<class Arg>
void f( void(*g)(Arg) );

void h(int);
void h(double);

template<class T>
void h2(T);

int main()
{
  void (*p)(int) = h;            // this works (std:13.4-1.1)
  void (*p2)(unsigned char) = h2;    // this works as well (std:13.4-1.1)
  f<int>(h2);  // this also works (std:13.4-1.3)

  // "Cannot generate template specialization from h(int)",
  // "Could not find a match for f<Arg>(void (*)(int))"
  f<double>(h);   // should work (std:13.4-1.3)

  f( (void(*)(double))h);  // C-style cast works (std:13.4-1.6 with 5.4)

  // "Overloaded 'h' ambiguous in this context"
  f(static_cast<void(*)(double)>(h)); // should work (std:13.4-1.6 with 5.2.9)
}

[string conversion] Converting const char * to std::string

#include <string>

template<class T>
void f(const std::string & s)
{}

int main()
{
  f<double>("hello");  // "Could not find a match for f<T>(char *)"
}

[template value defaults] Dependent default arguments for template value parameters

template<class T>
struct A
{
  static const bool value = true;
};

// "Templates must be classes or functions", "Declaration syntax error"
template<class T, bool v = A<T>::value>
struct B {};

int main()
{
  B<int> x;
}

[function partial ordering] Partial ordering of function templates

#include <iostream>

template<class T> struct A {};

template<class T1>
void f(const A<T1> &)
{
  std::cout << "f(const A<T1>&)\n";
}

template<class T>
void f(T)
{
  std::cout << "f(T)\n";
}

int main()
{
  A<double> a;
  f(a);   // output: f(T)  (wrong)
  f(1);   // output: f(T)  (correct)
}

[instantiate memfun ptr] Instantiation with member function pointer

template<class U> class C { };
template<class T>
class A
{
  static const int v = C<void (T::*)()>::value;
};

template<class U> class C { };
template<class T>
class A
{
  typedef void (T::*my_type)();
  static const int v = C<my_type>::value;
};

Library

[cmath.abs] Function double std::abs(double) missing

#include <cmath>

int main()
{
  double (*p)(double) = std::abs;  // error
}

Similar remarks apply to seemingly all of the other standard math functions, where Borland C++ fails to provide float and long double overloads.

Workaround: Use std::fabs instead if type genericity is not required.

Appendix: Additional issues with Borland C++ version 5.5

[inline friend] Inline friend functions in template classes

namespace N {
template<class T>
class A
{
  // "f is not a member of 'N' in function main()"
  friend bool f(T x, T y) { return x < y; }
};
}

int main()
{
  N::A<int> a;
}