Conclusions: I cannot link to a "*.a" library using the Windows linker. This is because these libraries are built with a dependency on the symbol __data_start__ which is a gcc construct.
If I can figure out the correct entry point then I can link to my manufactured cygwin DLL import library which seems to contain most of the contents of libc. I cannot use crt0.o with my import library because it does not define _cygwin_crt0 which crt0.o is dependent on. I could try building a DLL which wraps a library that supports either _cygwin_crt0 and then create an import library, but suspect this would not work. I could try building crt0.o into a DLL and generate an import library for that. This might work. I could get the source code for both crt0.o and cygwin_crt0() and build it into a DLL or link compatible static library. This might also work, but is more difficult. Alastair. On Wed, 2 Jun 2004 13:15:24 +0100 (GMT Daylight Time) Alastair Growcott <[EMAIL PROTECTED]> wrote: > Ok, so progress so far. By the way, a main reason I am posting this stuff is so that > in future anyone trying the same can search the archives and find all these posts. > If anyone reads it and actually helps me, that would be a bonus :) > > I now have what seems to be a proper import library for cygwin1.dll. I am stuck as > to what entry point I should specify. I expected cygwin1.dll to implement > mainCRTStartup, and have seen guides that suggest that when compiling programs under > cygwin using gcc, that you should specify manCRTStartup as the entry point with the > -e option. > > I have found that crt0.o implements mainCRTStartup(). Can anyone tell me what crt0.o > is for? However when I take that as well it then demands a symbol _cygwin_crt0 which > is defined in libc.a. If I take libc.a as well then I get loads of undefined symbols > which seem to be defined in libgcc.a somehow. > > If I specify main() as my entry point, I get it to compile with only those warnings > about the wrong attributes on the .text sections. However when I try and run it, it > just hangs. Running it through gdb and breaking it gives me the following stack; > > 0x7c5b9a91 in UnregisterConsoleIME () > from /cygdrive/c/WINNT/system32/KERNEL32.DLL > > Of course, this is probably wrong. > > I suspect that some of the people who wrote Cygwin could probably tell me exactly > what I need to do or why it is impossible and save me stumbling around blindly like > this. The question is, do they read this mailing list? > > > Alastair. > > > On Wed, 2 Jun 2004 10:17:18 +0100 (GMT Daylight Time) Alastair Growcott <[EMAIL > PROTECTED]> wrote: > > > So far so good - not. > > > > I am trying to link against the lib*.a files using the Visual Studio linker, and > > it seems to accept them. However I do get the following warning; > > > > libcygwin.a(d001126.o) : warning LNK4078: multiple '.text' sections found with > > different attributes (E0000020) > > > > Moreover when I try and run the executable, absolutely nothing happens. > > > > Now I remember reading somewhere that MSVCRT.DLL and cygwin1.dll are mutually > > exclusive, so I flange my makefile to add /NODEFAULTLIB on the link line. I now > > get the additional message; > > > > LINK : error LNK2001: unresolved external symbol _mainCRTStartup > > > > I know this is simple to fix, but my brain has just gone to sleep - any tips? > > > > Alastair. > > > > > > On Wed, 2 Jun 2004 09:51:52 +0100 Max Bowsher <[EMAIL PROTECTED]> wrote: > > > > > Alastair Growcott wrote: > > > > Hi. > > > > > > > > I have read all the FAQs and stuff. I have searched the web. I would like > > > a > > > > step by step list of instructions to achieve the following. > > > > > > > > I want to use check to test an MFC application. This means I must use the > > > > Visual Studio compiler, cl, and linker, link. > > > > Check calls fork(). This function is implemented in the cygwin1.dll. > > > > I cannot link using the DLL. I read somewhere that libcygwin.a is > > > equivalent > > > > to the cygwin1.lib, but when I try and link against it I get all sorts of > > > > bizarre symbols not found. According to cygcheck, cygwin1.dll only has > > > > dependencies on standard Windows DLLs that I am already linking against. > > > > > > > > So how do I; > > > > > > > > a) obtain a version of cygwin1.lib that I can link against using the > > > Visual > > > > Studio linker that will work nicely and neatly, or > > > > b) link against libcygwin.a using the Visual Studio linker. > > > > > > I don't think anyone has ever done this before, so I doubt very much whether > > > what you are looking for exists. > > > > > > If you are serious about doing this, you will likely need to figure it out > > > yourself, assuming of course, that it actually is possible at all. > > > > > > Max. > > > > > > > > > > > > > > > > > -- > Alastair Growcott > Software Maintenance Engineer > > BakBone Software > Merck House > Seldown Lane > Poole, BH15 1TW > P +44 (0)1202 241000 > F +44 (0)1202 249000 > [EMAIL PROTECTED] > www.bakbone.com > > > > -- Alastair Growcott Software Maintenance Engineer BakBone Software Merck House Seldown Lane Poole, BH15 1TW P +44 (0)1202 241000 F +44 (0)1202 249000 [EMAIL PROTECTED] www.bakbone.com > -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
