[Bug c++/98362] New: bad file data on Windows for C++ 20 module

[unlvsur at live dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98362

            Bug ID: 98362
           Summary: bad file data on Windows for C++ 20 module
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: unlvsur at live dot com
  Target Milestone: ---

I guess the reason is because of CRLF issue. You need to open module file with
_O_BINARY flag. Or msvcrt or ucrt will trigger them as a text stream. I guess
that is the solution

E:\mingw-w64-backup\msys64\home\unlvs\www>g++ -o main hello.cc main.cc -Ofast
-std=c++20 -s -fmodules-ts
In module imported at main.cc:1:1:
hello: error: failed to read compiled module: Bad file data
hello: note: compiled module file is 'gcm.cache/hello.gcm'
hello: fatal error: returning to the gate for a mechanical issue
compilation terminated.


hello.cc

module;
#include<cstdio>
export module hello;
export inline void greeter (char const* cstr) noexcept
{
        std::puts(cstr);
}

main.cc

import hello;
int main (void)
{
        greeter("Hello\n");
}