strange problems with C++ exceptions with mingw

问题

I have encountered a strange problems with exceptions using mingw and managed to cut it down to the following example:

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;

void test(int a) {
    if (a < 0) {
        throw std::ios_base::failure("a < 0");
    }
}
void test_file(std::string const & fName)
{
    std::ifstream inF(fName.c_str(), std::fstream::in);
    if (!inF) {
        cout << "file error -> throwing exception" << endl;
        throw ios_base::failure("could not open input file '" + fName + "'");
    }
}

int main()
{
    try { test(-5); }
    catch(std::exception& e) {
        cerr << "Exception caught: " << e.what() << " .. continue anyway" <<endl;
    }

    try { test_file("file-that-does-not-exist"); }
    catch(std::exception& e) {
        cerr << "Exception caught: " << e.what() << endl;
        exit(EXIT_FAILURE);
    }
    return EXIT_SUCCESS;
}

The first exception is caught, but the second one does not, so I get the nice Windows error-box informing me that my application has stopped working :-( The full command-line output is:

Exception caught: a < 0 .. continue anyway
file error -> throwing exception

This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information.

The same happen also with other exceptions (like std::runtime_error).

Am I doing something wrong, or is the problem somewhere else?

System info: Windows 7 x64, latest mingw32 (re-installed yesterday using mingw-get from mingw.org).

Thanks a lot in advance.
Michal

回答1:

FWIW, on XP SP3 with MingW:

Using built-in specs.
Target: mingw32
Configured with: ../gcc-4.4.0/configure --prefix=/mingw --build=mingw32 --enable-languages=c,ada,c++,fortran,objc,obj-c++ --disable-nls --disable-win32-registry --disable-werror --enable-threads --disable-symvers --enable-cxx-flags='-fno-function-sections -fno-data-sections' --enable-fully-dynamic-string --enable-libgomp --enable-version-specific-runtime-libs --enable-sjlj-exceptions --with-pkgversion='TDM-1 mingw32' --with-bugurl=http://www.tdragon.net/recentgcc/bugs.php
Thread model: win32
gcc version 4.4.0 (TDM-1 mingw32)

Results in a.exe:

    ntdll.dll => /cygdrive/c/WINDOWS/system32/ntdll.dll (0x7c900000)
    kernel32.dll => /cygdrive/c/WINDOWS/system32/kernel32.dll (0x7c800000)
    msvcrt.dll => /cygdrive/c/WINDOWS/system32/msvcrt.dll (0x77c10000)

Output

Exception caught: a < 0 .. continue anyway
file error -> throwing exception
Exception caught: could not open input file 'file-that-does-not-exist'

So this is soft evidence pointing in the direction of

library incompatibility
environmental differences
bug (?) in your version of MingW

回答2:

No, I don't think you're doing anything wrong there, this is pretty standard and works quite well under Linux.

I would suggest raising a query with the MinGW people. Even if it's not a bug, they should be able to tell you what's going on.

回答3:

I'm also having a problem with this (6 years later), except mine is found with MSYS2, cmake/ninja/mingw32 on windows 7:

CMakeLists.txt:

cmake_minimum_required(VERSION 3.6)
project(FailedExceptions )
add_executable(FailedExceptions  main.cpp foo.c)

Output:

$ cmake .. -GNinja
-- The C compiler identification is GNU 7.2.0
-- The CXX compiler identification is GNU 7.2.0
-- Check for working C compiler: C:/msys64/mingw32/bin/cc.exe -- works
-- Check for working CXX compiler: C:/msys64/mingw32/bin/c++.exe -- works
-- Configuring done
-- Generating done
-- Build files have been written to: C:/msys64/home/sferguson/src/vis/build

$ ninja -v
[1/3] C:\msys64\mingw32\bin\cc.exe    -MD -MT CMakeFiles/FailedExceptions.dir/PortDescription.c.obj -MF CMakeFiles\FailedExceptions.dir\PortDescription.c.obj.d -o CMakeFiles/FailedExceptions.dir/PortDescription.c.obj   -c ../PortDescription.c
[2/3] C:\msys64\mingw32\bin\c++.exe     -MD -MT CMakeFiles/FailedExceptions.dir/main.cpp.obj -MF CMakeFiles\FailedExceptions.dir\main.cpp.obj.d -o CMakeFiles/FailedExceptions.dir/main.cpp.obj -c ../main.cpp
[3/3] cmd.exe /C "cd . && C:\msys64\mingw32\bin\c++.exe    CMakeFiles/FailedExceptions.dir/main.cpp.obj CMakeFiles/FailedExceptions.dir/PortDescription.c.obj  -o FailedExceptions.exe -Wl,--major-image-version,0,--minor-image-version,0  -lgcc_eh -lgcc_eh -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32 && cd ."

$ ./FailedExceptions.exe
Exception caught: a < 0: iostream error
file error -> throwing exception

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

The only catch is that I also need to link some (any) c file, even if I don't use anything it provides. In this case I did it with foo.c:

int foo() { return 0; }

来源：https://stackoverflow.com/questions/7765599/strange-problems-with-c-exceptions-with-mingw

标签

c++

exception-handling

mingw32