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Issue of the Implementation # S0677

Brief

num_put<>::do_put(void*) performs padding incorrectly when adjustfield==internal

Detailed Description

The following member function of num_put<char> and num_put<wchar_t>

iter_type put(iter_type out, ios_base& str, char_type fill, const void* val) const

incorrectly performs padding of a string to bring its length to the required value if 'adjustfield' flag is equal to 'internal': instead of adding fill characters after "0x" it adds them at the beginning of the string

According to the description of padding options (22.2.2.2.2 p19), if

adjustfield == internal and representation after stage 1 began with 0x or 0X - pad after x or X.

The example below demonstrates the problem (the output of numbers to cout is implemented using num_get<> facet).

In this example "  0x1" is output to the standard output stream while it should be "0x  1" according to the standard.

Problem location(s) in the standard

Linux Standard Base C++ Specification 3.2, Chapter 9. Libraries, 9.1. Interfaces for libstdcxx that refers ISO/IEC 14882: 2003 Programming languages -- C++, section 22.2.2.2.2

Example

#include <iostream>
#include <locale>

using namespace std;
int main()
{
    void *p = (void*)0x1;
    cout.width(5);
    cout << internal << p << endl;
    // "  0x1" will be output while it should be "0x  1"
    return 0;
}

Component

libstdc++

Accepted

GCC Bugzilla 38210

Status

Fixed in gcc-4.4.0

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