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c++ - freopen hangs when using -L/ENTRY:_WinMain 16

reply "Wichetael" <wichetael gmx.net> writes:
When using this source:

----
  #include <stdio.h>
  #include <windows.h>

  int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, UINT
nSW) {
    FILE* newfp = freopen(TEXT("Testing.log"), TEXT("w"), stdout);
    printf(TEXT("Testing..."));

    return 0;
  }
----

and this command line:  dmc src\test2.cpp -o
test\test2.exe -L/ENTRY:_WinMain 16

The program hangs on executing freopen, when I leave out the -L switch
everything works fine. This seems really strange to me, how can specifying
the entry point (which should be the same as when not using the -L switch)
have such a strange result?

You might ask why I'm using the -L switch, that is because I want to use a
library which implements WinMain and OPTLINK does not look for entry points
in the library files, only in object files. Which in itself seems somewhat
strange to me, Walter, if you would, please have OPTLINK also look for entry
points in library files. I am using version 8.39.5n

Regards, Remko van der Vossen
Feb 20 2004
parent reply "Walter" <walter digitalmars.com> writes:
"Wichetael" <wichetael gmx.net> wrote in message
news:c159hl$2fcn$1 digitaldaemon.com...
 When using this source:

 ----
   #include <stdio.h>
   #include <windows.h>

   int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine,

 nSW) {
     FILE* newfp = freopen(TEXT("Testing.log"), TEXT("w"), stdout);
     printf(TEXT("Testing..."));

     return 0;
   }
 ----

 and this command line:  dmc src\test2.cpp -o
 test\test2.exe -L/ENTRY:_WinMain 16

 The program hangs on executing freopen, when I leave out the -L switch
 everything works fine. This seems really strange to me, how can specifying
 the entry point (which should be the same as when not using the -L switch)
 have such a strange result?

That will happen when the startup code gets skipped. You're writing a 16 bit windows program, you need to specify the right acrtused - see www.digitalmars.com/ctg/acrtused.html - using a flag to the compiler.
 You might ask why I'm using the -L switch, that is because I want to use a
 library which implements WinMain and OPTLINK does not look for entry

 in the library files, only in object files. Which in itself seems somewhat
 strange to me, Walter, if you would, please have OPTLINK also look for

 points in library files. I am using version 8.39.5n

 Regards, Remko van der Vossen

If that's happening, extract the .obj file from the library and link it explicitly.
Feb 20 2004
parent reply "Wichetael" <wichetael gmx.net> writes:
"Walter" <walter digitalmars.com> wrote in message
news:c15h87$30om$2 digitaldaemon.com...
 "Wichetael" <wichetael gmx.net> wrote in message
 news:c159hl$2fcn$1 digitaldaemon.com...
 When using this source:

 ----
   #include <stdio.h>
   #include <windows.h>

   int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine,

 nSW) {
     FILE* newfp = freopen(TEXT("Testing.log"), TEXT("w"), stdout);
     printf(TEXT("Testing..."));

     return 0;
   }
 ----

 and this command line:  dmc src\test2.cpp -o
 test\test2.exe -L/ENTRY:_WinMain 16

 The program hangs on executing freopen, when I leave out the -L switch
 everything works fine. This seems really strange to me, how can


 the entry point (which should be the same as when not using the -L


 have such a strange result?

That will happen when the startup code gets skipped. You're writing a 16

 windows program, you need to specify the right acrtused - see
 www.digitalmars.com/ctg/acrtused.html - using a flag to the compiler.

Actualy it's a win32 program, not win16. The strange thing is that I know I've used a construction like this before without trouble, so since then something has changed, unfortunately I don't remember which dmc version I used at the time. But why should it make any difference if the entry point is chosen by the compiler or specified by a command line switch... -mn and -WA do not seem to help, what command line switches should I be looking for?? obj2asm on test2.obj gets me a extrn __acrtused
 You might ask why I'm using the -L switch, that is because I want to use


 library which implements WinMain and OPTLINK does not look for entry

 in the library files, only in object files. Which in itself seems


 strange to me, Walter, if you would, please have OPTLINK also look for

 points in library files. I am using version 8.39.5n

 Regards, Remko van der Vossen

If that's happening, extract the .obj file from the library and link it explicitly.

I'd rather not, and similarly, why should it matter whether the label is in a library or in an object file Regadrs, Remko van der Vossen
Feb 21 2004
parent "Walter" <walter digitalmars.com> writes:
"Wichetael" <wichetael gmx.net> wrote in message
news:c18dir$2cmn$1 digitaldaemon.com...
 "Walter" <walter digitalmars.com> wrote in message
 news:c15h87$30om$2 digitaldaemon.com...
 "Wichetael" <wichetael gmx.net> wrote in message
 news:c159hl$2fcn$1 digitaldaemon.com...
 When using this source:

 ----
   #include <stdio.h>
   #include <windows.h>

   int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR



 UINT
 nSW) {
     FILE* newfp = freopen(TEXT("Testing.log"), TEXT("w"), stdout);
     printf(TEXT("Testing..."));

     return 0;
   }
 ----

 and this command line:  dmc src\test2.cpp -o
 test\test2.exe -L/ENTRY:_WinMain 16

 The program hangs on executing freopen, when I leave out the -L switch
 everything works fine. This seems really strange to me, how can


 the entry point (which should be the same as when not using the -L


 have such a strange result?

That will happen when the startup code gets skipped. You're writing a 16

 windows program, you need to specify the right acrtused - see
 www.digitalmars.com/ctg/acrtused.html - using a flag to the compiler.

Actualy it's a win32 program, not win16.

Ok, but the startup code still needs to get executed.
 The strange thing is that I know
 I've used a construction like this before without trouble, so since then
 something has changed, unfortunately I don't remember which dmc version I
 used at the time. But why should it make any difference if the entry point
 is chosen by the compiler or specified by a command line switch...

The need is getting the right _acrtused symbol defined so the right startup code gets linked in. Just having the start address right is not sufficient.
 -mn and -WA do not seem to help, what command line switches should I be
 looking for?? obj2asm on test2.obj gets me a extrn __acrtused

www.digitalmars.com/ctg/acrtused.html should give that info for the various scenarios.
 I'd rather not, and similarly, why should it matter whether the label is

 a library or in an object file

It shouldn't. That would be a bug if it is happening.
Feb 21 2004