<system_error>: passes a temporary string to runtime_error

[mihaisebea]

system_error class gives runtime error a temporary std string
https://github.com/microsoft/STL/blob/main/stl/inc/system_error#L477

and runtime_error seems to pass a temporary string to exception

explicit runtime_error(const string& _Message) : _Mybase(_Message.c_str()) {}

if _HAS_EXCEPTIONS is defined to 1 it seems exception class does copy the string

 __std_exception_copy(&_InitData, &_Data);

but if _HAS_EXCEPTIONS = 0 the exception class only stores a pointer

const char* _Ptr; // the message pointer

Command-line test case

C:\Temp>type repro.cpp
#include <iostream>

int main() {
  
    std::string error_what("test system_error");
    std::error_code error_code(0, std::system_category());				
    auto se = std::system_error(error_code, error_what);    
    std::puts(se.what());

}

C:\Test>cl /W4 /WX /D "_HAS_EXCEPTIONS=0" /MDd .\test.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31935 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

test.cpp
Microsoft (R) Incremental Linker Version 14.34.31935.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:test.exe
test.obj

C:\Test>test.exe
¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦¦

Expected behavior
For the a proper message to be printed instead of garbage

C:\Test>cl /EHsc /W4 /WX /MDd .\test.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 19.34.31935 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

test.cpp
Microsoft (R) Incremental Linker Version 14.34.31935.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:test.exe
test.obj

C:\Test>test.exe
test system_error: La operaci¾n se complet¾ correctamente.

STL version
Microsoft Visual Studio Community 2022 (64-bit) - Current Version 17.4.2
Additional context
At this point it's hard for me to assume that I found a legit bug and nobody is using _HAS_EXCEPTIONS=0
but all my c++ experts are in vacation already :) 🤷‍♂️

[AlexGuteniev]

Duplicate of #2114