gcc builtin functions, e.g. memcpy, and namespace std

["Anthony Williams" <anthony_w dot geo at yahoo dot com>]

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GCC defines some builtin functions for simple operations, such as
memcpy and strlen.

In C++, these should be in namespace std. However, defining a copy in
namespace std leads to the possibility of a compilation error

#include <cstring>

using namespace std;

int main()
{
  char buf1[50]="hello";
  char buf2[50];

  memcpy(buf2,buf1,50);
}

error - ambiguous use of memcpy
candidates are std::memcpy
<internal> memcpy

I have two suggestions:

1. Disable these builtins for C++, since they can be defined as
inlines in the headers anyway, by making -fno-builtin default for C++
2. Put them in namespace std:: when compiling C++, so they work just
as for C - silently being used instead of the library version where
possible

The third alternative, which is to force users to specify ::memcpy or
std::memcpy is not pleasant.

Anthonyc

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