我遇到了麻烦超过4GB的限制为stringstream的，即使是在有足够的内存64位Linux机器上运行。
测试代码如下（阅读您的意见后修订）4GB后核心转储。
从gdb的跟踪，字符串流使用默认的std :: char_traits其中INT_TYPE设置为32位整型，而不是64位的size_t。 任何建议来解决？
#include <stdint.h>
#include <iostream>
#include <sstream>
#include <math.h>
using namespace std;
int main(int narg, char** argv)
{
string str;
stringstream ss;
const size_t GB = (size_t)pow(2, 30);
str.resize(GB, '1');
cerr << "1GB=" << str.size()
<< ", string::max_size=" << str.max_size()/GB << "GB"
<< ", sizeof(int)=" << sizeof(int)
<< ", sizeof(int64_t)=" << sizeof(int64_t)
<< ", sizeof(size_t)=" << sizeof(size_t)
<< endl;
string().swap(str);
str.resize(6*GB, '6');
cerr << "str.size()=" << (str.size() / GB) << "GB allocated successfully"
<< ", ended with " << str.substr(str.size()-5, 5) << endl;
string().swap(str);
str.resize(GB/4, 'Q');
cerr << "writing to stringstream..." << std::flush;
for (int i = 0; i < 30; ++i) {
ss << str << endl;
cerr << double(ss.str().size())/GB << "GB " << std::flush;
}
cerr << endl;
exit(0);
}
输出是：
1GB=1073741824, string::max_size=4294967295GB, sizeof(int)=4, sizeof(int64_t)=8, sizeof(size_t)=8
str.size()=6GB allocated successfully, ended with 66666
writing to stringstream...0.25GB 0.5GB 0.75GB 1GB 1.25GB 1.5GB 1.75GB 2GB 2.25GB 2.5GB 2.75GB 3GB 3.25GB 3.5GB 3.75GB Segmentation fault (core dumped)
gdb的堆栈跟踪：
(gdb) where
#0 0x00002aaaaad5e0c1 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::overflow(int) () from /usr/lib64/libstdc++.so.6
#1 0x00002aaaaad62cbd in std::basic_streambuf<char, std::char_traits<char> >::xsputn(char const*, long) () from /usr/lib64/libstdc++.so.6
#2 0x00002aaaaad5657d in std::basic_ostream<char, std::char_traits<char> >& std::operator<< <char, std::char_traits<char>, std::allocator<char> >(std::basic_ostream<char, std::char_traits<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) () from /usr/lib64/libstdc++.so.6
#3 0x000000000040112b in main ()
二进制似乎是64位。
$ file a.out
a.out: ELF 64-bit LSB executable, AMD x86-64, version 1 (SYSV), for GNU/Linux 2.6.9, dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped
尼克，在检查预处理器输出好点。 不知怎么的std :: char_straits覆盖__gnu_cxx :: char_straits，并重新定义INT_TYPE为int，而不是无符号只要__gnu_cxx :: char_straits。 这是非常令人惊讶！
namespace __gnu_cxx
{
# 61 "/usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/char_traits.h" 3
template <class _CharT>
struct _Char_types
{
typedef unsigned long int_type;
typedef std::streampos pos_type;
typedef std::streamoff off_type;
typedef std::mbstate_t state_type;
};
# 86 "/usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/char_traits.h" 3
template<typename _CharT>
struct char_traits
{
typedef _CharT char_type;
typedef typename _Char_types<_CharT>::int_type int_type;
typedef typename _Char_types<_CharT>::pos_type pos_type;
typedef typename _Char_types<_CharT>::off_type off_type;
typedef typename _Char_types<_CharT>::state_type state_type;
....
};
namespace std
{
# 224 "/usr/lib/gcc/x86_64-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/char_traits.h" 3
template<class _CharT>
struct char_traits : public __gnu_cxx::char_traits<_CharT>
{ };
template<>
struct char_traits<char>
{
typedef char char_type;
typedef int int_type;
typedef streampos pos_type;
typedef streamoff off_type;
typedef mbstate_t state_type;
...
};
编辑：下面从STL网站http://www.cplusplus.com/reference/string/char_traits/其中char_traits专业化使用int类型。
typedef INT_T int_type;
Where INT_T is a type that can represent all the valid characters representable by a char_type plus an end-of-file value (eof) which is compatible with iostream class member functions.
For char_traits<char> this is int, and for char_traits<wchar_t> this is wint_t
