On Monday 13 October 2025 14:30:59 Martin Storsjö wrote:
> On Thu, 9 Oct 2025, Pali Rohár wrote:
>
> > On Thursday 09 October 2025 16:07:34 Martin Storsjö wrote:
> > > On Sun, 5 Oct 2025, Pali Rohár wrote:
> > >
> > > > msvcrt and UCRT function _chsize() has same behavior and also ABI as
> > > > POSIX
> > > > function ftruncate() with 32-bit length.
> > > >
> > > > For 64-bit length msvcr80+ and UCRT provide function _chksize_s() but it
> > > > has slightly different usage as _chksize() / ftruncate() and so cannot
> > > > be
> > > > directly aliased at symbol ABI level.
> > > >
> > > > Function _chksize_s() calls invalid parameter exception handler and
> > > > return
> > > > value is errno.
> > > >
> > > > mingw-w64 currently provides its own ftruncate64() implementation which
> > > > is
> > > > statically linked into every binary which calls ftruncate64().
> > > >
> > > > For msvcr80+ and UCRT builds, provide a new ftruncate64()
> > > > implementation as
> > > > a simple wrapper around the CRT _chksize_s() function. To prevent
> > > > calling
> > > > invalid parameter exception handler, validate input parametes manually
> > > > before calling the function itself.
> > > >
> > > > For pre-msvcr80 builds use the existing mingw-w64 implemenation of
> > > > ftruncate64() function.
> > > >
> > > > And for OS-system msvcrt.dll builds use either the _chksize_s() or the
> > > > mingw-w64 implemation. Function symbol _chksize_s in msvcrt.dll is
> > > > available since Windows Vista, so for x86/x64 builds, resolve that
> > > > symbol
> > > > at runtime.
> > > >
> > > > Note that OS-system msvcrt.dll _chksize_s() does not call invalid
> > > > parameter
> > > > exception handler, so call function directly without validation.
> > > >
> > > > To prevent symbol conflicts between existing mingw-w64 implementation of
> > > > ftruncate64 and new wrapper implementation (around _chksize_s), rename
> > > > the
> > > > existing mingw-w64 implementation to __mingw_ftruncate64.
> > > >
> > > > With this change, calling the ftruncate64 function symbol results in
> > > > using
> > > > the native _chksize_s CRT implementation for msvcr80+ and UCRT builds.
> > > > ---
> > > > mingw-w64-crt/Makefile.am | 5 +-
> > > > .../{ftruncate64.c => mingw_ftruncate64.c} | 6 ++-
> > > > mingw-w64-crt/stdio/msvcr80plus_ftruncate64.c | 30 ++++++++++++
> > > > mingw-w64-crt/stdio/msvcrtos_ftruncate64.c | 47 +++++++++++++++++++
> > > > 4 files changed, 86 insertions(+), 2 deletions(-)
> > > > rename mingw-w64-crt/stdio/{ftruncate64.c => mingw_ftruncate64.c} (98%)
> > > > create mode 100644 mingw-w64-crt/stdio/msvcr80plus_ftruncate64.c
> > > > create mode 100644 mingw-w64-crt/stdio/msvcrtos_ftruncate64.c
> > > >
> > > > diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
> > > > index 705624635acf..ca3e85264172 100644
> > > > --- a/mingw-w64-crt/Makefile.am
> > > > +++ b/mingw-w64-crt/Makefile.am
> > > > @@ -363,6 +363,7 @@ src_msvcrt=\
> > > > secapi/wmemmove_s.c \
> > > > stdio/_ftelli64.c \
> > > > stdio/mingw_lock.c \
> > > > + stdio/msvcrtos_ftruncate64.c \
> > > > stdio/msvcr110pre_stat32.c \
> > > > stdio/msvcr110pre_stat64i32.c \
> > > > stdio/msvcr110pre_wstat32.c \
> > > > @@ -933,6 +934,7 @@ src_pre_msvcr80=\
> > > > stdio/_stat64i32.c \
> > > > stdio/_wstat64i32.c \
> > > > stdio/mingw_lock.c \
> > > > + stdio/msvcr80pre_ftruncate64.c \
> > > > string/msvcr80pre_wcstok.c
> > >
> > > There's no msvcr80pre_ftruncate64.c included in this patchset.
> > >
> > > // Martin
> >
> > Ou, I really forgot to git add it. Here is the missing part:
> >
> > fixup! crt: Provide ftruncate64 function via wrapper around native CRT
> > function _chsize_s
>
> Thanks; with this inline patch manually applied, I managed to get the build
> to proceed a bit further.
>
> Building GCC/libstdc++ configured for UCRT now fails:
>
> https://github.com/mstorsjo/mingw-w64/actions/runs/18460823661/job/52591697068
>
> /home/runner/work/mingw-w64/mingw-w64/gcc-14.1.0/build/../../prefix/x86_64-w64-mingw32/bin/ld:
> ../src/c++17/.libs/libc++17convenience.a(cow-fs_ops.o): in function
> `std::filesystem::__gnu_posix::truncate64(wchar_t const*, long long)':
> /home/runner/work/mingw-w64/mingw-w64/gcc-14.1.0/build/x86_64-w64-mingw32/libstdc++-v3/src/c++17/../../../../../libstdc++-v3/src/c++17/../filesystem/ops-common.h:175:(.text$_ZNSt10filesystem11resize_fileERKNS_4pathEyRSt10error_code+0x4b):
> undefined reference to `ftruncate64'
> /home/runner/work/mingw-w64/mingw-w64/gcc-14.1.0/build/../../prefix/x86_64-w64-mingw32/bin/ld:
> ../src/c++17/.libs/libc++17convenience.a(fs_ops.o): in function
> `std::filesystem::__gnu_posix::truncate64(wchar_t const*, long long)':
> /home/runner/work/mingw-w64/mingw-w64/gcc-14.1.0/build/x86_64-w64-mingw32/libstdc++-v3/src/c++17/../../../../../libstdc++-v3/src/c++17/../filesystem/ops-common.h:175:(.text$_ZNSt10filesystem11resize_fileERKNS_7__cxx114pathEyRSt10error_code+0x4b):
> undefined reference to `ftruncate64'
> collect2: error: ld returned 1 exit status
> make[5]: *** [Makefile:764: libstdc++.la] Error 1
I see... for 64-bit UCRT is missing the msvcr80plus_ftruncate64.c object
file in the import library. It was only in msvcrt and versioned msvcrt*.
diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index ca3e85264172..ff75b60a0a51 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -430,6 +430,7 @@ src_ucrtbase=\
misc/_onexit.c \
misc/output_format.c \
misc/ucrt-access.c \
+ stdio/msvcr80plus_ftruncate64.c \
stdio/ucrt___local_stdio_printf_options.c \
stdio/ucrt___local_stdio_scanf_options.c \
stdio/ucrt__scprintf.c \
>
> It really feels like a waste of time that I have to try to apply your
> patches from email and feed them to a system for testing compilation, and
> then manually feedback the test results to you.
>
> // Martin
Sorry for that :-(
_______________________________________________
Mingw-w64-public mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/mingw-w64-public
