C++ C++;gcc下的SEGFULT+;mingw而非gcc+;linux
我在Mingw下有一个sefault,但在Linux下没有。我设法将其简化为以下代码:C++ C++;gcc下的SEGFULT+;mingw而非gcc+;linux,c++,gcc,mingw,C++,Gcc,Mingw,我在Mingw下有一个sefault,但在Linux下没有。我设法将其简化为以下代码: #include <iostream> #include <string> #include <map> using namespace std; const std::string& getConfiguration(const std::string& key, std::map<std::string, std::string> con
#include <iostream>
#include <string>
#include <map>
using namespace std;
const std::string& getConfiguration(const std::string& key, std::map<std::string, std::string> configuration)
{
map<string, string>::const_iterator it = configuration.find(key);
return it->second;
}
int main() {
map<string, string> testmap;
testmap["key"] = "value";
map<string, string>::const_iterator it;
it = testmap.find("key");
const string& value = it->second;
cout << value << endl;
cout << "ok!" << endl;
const string& valuebis = getConfiguration("key", testmap);
cout << valuebis << endl;
cout << "Mingw segfaults before here" << endl;
return 0;
}
(但是我得到了与i686-pc-mingw32.static相同的结果)并且我在gdb中得到了以下错误:
Starting program: Z:\test-conv.exe
[New Thread 17328.0x43b4]
value
ok!
Program received signal SIGSEGV, Segmentation fault.
std::operator<< <char, std::char_traits<char>, std::allocator<char> > (__os=warning: RTTI symbol not found for class 'std::ostream'
..., __str=<error reading variable: Cannot access memory at address 0xfeeefee2>)
at /home/eroux/softs/mxe-64/tmp-gcc-i686-w64-mingw32.static/gcc-4.9.1.build/i686-w64-mingw32.static/libstdc++-v3/include/bits/basic_string.h:2777
2777 /home/eroux/softs/mxe-64/tmp-gcc-i686-w64-mingw32.static/gcc-4.9.1.build/i686-w64-mingw32.static/libstdc++-v3/include/bits/basic_string.h: No such file or directory.
(gdb) bt
#0 std::operator<< <char, std::char_traits<char>, std::allocator<char> > (__os=warning: RTTI symbol not found for class 'std::ostream'
..., __str=<error reading variable: Cannot access memory at address 0xfeeefee2>)
at /home/eroux/softs/mxe-64/tmp-gcc-i686-w64-mingw32.static/gcc-4.9.1.build/i686-w64-mingw32.static/libstdc++-v3/include/bits/basic_string.h:2777
#1 0x0040181a in main () at ConventionTest.cpp:22
启动程序:Z:\test-conv.exe
[新螺纹17328.0x43b4]
价值
好啊
程序接收信号SIGSEGV,分段故障。
std::operatorgetConfiguration
返回对本地对象的引用(因此调用UB),将configuration
作为常量引用传递(或返回字符串的副本)。这是因为。原因是在getConfiguration
函数中,您通过值传递映射,然后返回对此映射中某个条目的引用,该引用将在函数返回时被销毁
Starting program: Z:\test-conv.exe
[New Thread 17328.0x43b4]
value
ok!
Program received signal SIGSEGV, Segmentation fault.
std::operator<< <char, std::char_traits<char>, std::allocator<char> > (__os=warning: RTTI symbol not found for class 'std::ostream'
..., __str=<error reading variable: Cannot access memory at address 0xfeeefee2>)
at /home/eroux/softs/mxe-64/tmp-gcc-i686-w64-mingw32.static/gcc-4.9.1.build/i686-w64-mingw32.static/libstdc++-v3/include/bits/basic_string.h:2777
2777 /home/eroux/softs/mxe-64/tmp-gcc-i686-w64-mingw32.static/gcc-4.9.1.build/i686-w64-mingw32.static/libstdc++-v3/include/bits/basic_string.h: No such file or directory.
(gdb) bt
#0 std::operator<< <char, std::char_traits<char>, std::allocator<char> > (__os=warning: RTTI symbol not found for class 'std::ostream'
..., __str=<error reading variable: Cannot access memory at address 0xfeeefee2>)
at /home/eroux/softs/mxe-64/tmp-gcc-i686-w64-mingw32.static/gcc-4.9.1.build/i686-w64-mingw32.static/libstdc++-v3/include/bits/basic_string.h:2777
#1 0x0040181a in main () at ConventionTest.cpp:22