[PATCH v5 0/2] MR10250: Call abort if _wassert error behavior is set to _OUT_TO_STDERR and trigger a debug break.

[Santino Mazza (＠tati)]

If assert is called when error mode is set to _OUT_TO_STDERR and abort behavior is set to _WRITE_ABORT_MSG the abort message box is still showed in Windows. Some applications do this and don't trigger a break point in Wine because abort is never called.

Note: Windows actually triggers an exception in abort, instead of calling DebugBreak. I suppose this is the behavior of ReportFault, but it's not implemented.

--
  v5: msvcrt: Call abort at the end of _wassert.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10250

[PATCH v5 1/2] ucrtbase: Fastfail if _CALL_REPORTFAULT is set.

[Santino Mazza]

From: Santino Mazza <[e-mail]>

---
 dlls/msvcrt/exit.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/dlls/msvcrt/exit.c b/dlls/msvcrt/exit.c
index c8db6c405da..e018b330522 100644
--- a/dlls/msvcrt/exit.c
+++ b/dlls/msvcrt/exit.c
@@ -265,7 +265,14 @@ void CDECL abort(void)
       _cputs("\nabnormal program termination\n");
   }
 #endif
+
   raise(SIGABRT);
+
+#if _MSVCR_VER >= 140
+  if (MSVCRT_abort_behavior & _CALL_REPORTFAULT)
+    __fastfail(FAST_FAIL_FATAL_APP_EXIT);
+#endif
+
   /* in case raise() returns */
   _exit(3);
 }
@@ -279,8 +286,6 @@ unsigned int CDECL _set_abort_behavior(unsigned int flags, unsigned int mask)
   unsigned int old = MSVCRT_abort_behavior;
 
   TRACE("%x, %x\n", flags, mask);
-  if (mask & _CALL_REPORTFAULT)
-    FIXME("_WRITE_CALL_REPORTFAULT unhandled\n");
 
   MSVCRT_abort_behavior = (MSVCRT_abort_behavior & ~mask) | (flags & mask);
   return old;
-- 
GitLab


https://gitlab.winehq.org/wine/wine/-/merge_requests/10250

[PATCH v5 2/2] msvcrt: Call abort at the end of _wassert.

[Santino Mazza]

From: Santino Mazza <[e-mail]>

If assert is called when error mode is set to _OUT_TO_STDERR and
abort behavior is set to _WRITE_ABORT_MSG the abort message box is
still showed in Windows. Some applications do this and the abort
exception is still raised in the debugger on Windows.
---
 dlls/msvcrt/exit.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/dlls/msvcrt/exit.c b/dlls/msvcrt/exit.c
index e018b330522..481b8b5e3f7 100644
--- a/dlls/msvcrt/exit.c
+++ b/dlls/msvcrt/exit.c
@@ -305,12 +305,12 @@ void DECLSPEC_NORETURN CDECL _wassert(const wchar_t* str, const wchar_t* file, u
     wchar_t text[2048];
     _snwprintf(text, sizeof(text), L"File: %ls\nLine: %d\n\nExpression: \"%ls\"", file, line, str);
     DoMessageBoxW(L"Assertion failed!", text);
+    raise(SIGABRT);
+    _exit(3);
   }
-  else
-    fwprintf(stderr, L"Assertion failed: %ls, file %ls, line %d\n\n", str, file, line);
 
-  raise(SIGABRT);
-  _exit(3);
+  fwprintf(stderr, L"Assertion failed: %ls, file %ls, line %d\n\n", str, file, line);
+  abort();
 }
 
 /*********************************************************************
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10250

[Piotr Caban (＠piotr)]

On Wed Mar 11 13:24:48 2026 +0000, Santino Mazza wrote:
> I think it might be implemented differently, because I don't get any
> exceptions or breakpoints in x86dbg when `_CALL_REPORT_FAULT` is set in
> msvcr, only with ucrtbase.
> It's hard to comment without seeing your tests but I have checked that I'm getting an 0xc0000409 exception with msvcr120.dll.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10250#note_131834