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diff --git a/winsup/doc/faq-programming.xml b/winsup/doc/faq-programming.xml deleted file mode 100644 index af08be354..000000000 --- a/winsup/doc/faq-programming.xml +++ /dev/null @@ -1,873 +0,0 @@ -<!-- faq-programming.xml --> - -<qandaentry id="faq.programming.packages"> -<question><para>How do I contribute a package?</para></question> -<answer> - -<para>If you are willing to be a package maintainer, great! We urgently need -volunteers to prepare and maintain packages, because the priority of the -Cygwin Team is Cygwin itself. -</para> -<para>The Cygwin Package Contributor's Guide at -<ulink url="http://cygwin.com/setup.html">http://cygwin.com/setup.html</ulink> details everything you need to know -about being a package maintainer. The quickest way to get started is to -read the <emphasis>Initial packaging procedure, script-based</emphasis> section on -that page. The <literal>generic-build-script</literal> found there works well for -most packages. -</para> -<para>For questions about package maintenance, use the cygwin-apps mailing -list (start at <ulink url="http://cygwin.com/lists.html">http://cygwin.com/lists.html</ulink>) <emphasis>after</emphasis> -searching and browsing the cygwin-apps list archives, of course. Be -sure to look at the <emphasis>Submitting a package</emphasis> checklist at -<ulink url="http://cygwin.com/setup.html">http://cygwin.com/setup.html</ulink> before sending an ITP (Intent To -Package) email to cygwin-apps. -</para> -<para>You should also announce your intentions to the general cygwin list, in -case others were thinking the same thing. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.contribute"> -<question><para>How do I contribute to Cygwin?</para></question> -<answer> - -<para>If you want to contribute to Cygwin itself, see -<ulink url="http://cygwin.com/contrib.html">http://cygwin.com/contrib.html</ulink>. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.huge-executables"> -<question><para>Why are compiled executables so huge?!?</para></question> -<answer> - -<para>By default, gcc compiles in all symbols. You'll also find that gcc -creates large executables on UNIX. -</para> -<para>If that bothers you, just use the 'strip' program, part of the binutils -package. Or compile with the <literal>-s</literal> option to gcc. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.glibc"> -<question><para>Where is glibc?</para></question> -<answer> - -<para>Cygwin does not provide glibc. It uses newlib instead, which provides -much (but not all) of the same functionality. Porting glibc to Cygwin -would be difficult. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.objective-c"> -<question><para>Where is Objective C?</para></question> -<answer> - -<para>Objective C is not distributed with the Cygwin version of gcc, and there -are no plans to do so. The gcc package maintainer had difficulty -building it, and once built there were problems using it. It appears -that there is only minimal support for the Objective C front-end in the -main GCC distribution, anyway. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.make-execvp"> -<question><para>Why does my make fail on Cygwin with an execvp error? </para></question> -<answer> - -<para>First of all, if you are using <literal>make -j[N]</literal>, then stop. It doesn't -work well. Also beware of using non-portable shell features in your -Makefiles (see tips at <ulink -url="http://cygwin.com/faq/faq.using.html#faq.using.shell-scripts" />). -</para> -<para>Errors of <literal>make: execvp: /bin/sh: Illegal Argument</literal> or -<literal>make: execvp: /bin/sh: Argument list too long</literal> are often -caused by the command-line being to long for the Windows execution model. -To circumvent this, mount the path of the executable using the -X switch -to enable cygexec for all executables in that folder; you will also need -to exclude non-cygwin executables with the -x switch. Enabling cygexec -causes cygwin executables to talk directly to one another, which increases -the command-line limit. To enable cygexec for <literal>/bin</literal> and -<literal>/usr/bin</literal>, you can use these commands in a batch file: -</para> -<screen> -mount -X -b -f c:\cygwin\bin /bin -mount -X -b -f c:\cygwin\bin /usr/bin -mount -x -b -f c:\cygwin\bin\tclsh84.exe /usr/bin/tclsh84.exe -mount -x -b -f c:\cygwin\bin\tclsh84.exe /bin/tclsh84.exe -mount -x -b -f c:\cygwin\bin\wish84.exe /usr/bin/wish84.exe -mount -x -b -f c:\cygwin\bin\wish84.exe /bin/wish84.exe -</screen> - -<para>Note that if you have Tcl/Tk installed, you must specifically exclude -<literal>tclsh84</literal> and <literal>wish84</literal>, which are linked -to the Cygwin DLL but are not actually Cygwin programs. If you have added -other non-Cygwin programs to a path you want to mount cygexec, you can find -them with a script like this: -</para> -<screen> -#!/bin/sh -cd /bin; for f in `find . -type f -name '*.exe'`; do - cygcheck $f | (fgrep -qi cygwin1.dll || echo $f) -done -</screen> - -<para> -See <ulink url="http://www.cygwin.com/cygwin-ug-net/using-utils.html#mount" /> -for more information on using mount. -</para> - -</answer></qandaentry> - -<qandaentry id="faq.programming.winmain"> -<question><para>Why the undefined reference to <literal>WinMain@16</literal>?</para></question> -<answer> - -<para>If you're using <literal>gcc</literal>, try adding an empty main() function to one -of your sources. Or, perhaps you have <literal>-lm</literal> too early in the -link command line. It should be at the end: -</para> -<screen> - bash$ gcc hello.c -lm - bash$ ./a.exe - Hello World! -</screen> - -<para>works, but -</para> -<screen> - bash$ gcc -lm hello.c - /c/TEMP/ccjLEGlU.o(.text+0x10):hello.c: multiple definition of `main' - /usr/lib/libm.a(libcmain.o)(.text+0x0):libcmain.c: first defined here - /usr/lib/libm.a(libcmain.o)(.text+0x6a):libcmain.c: undefined reference to `WinMain@16' - collect2: ld returned 1 exit status -</screen> - -<para>If you're using GCJ, you need to pass a "--main" flag: -</para> -<screen> -gcj --main=Hello Hello.java -</screen> - -</answer></qandaentry> - -<qandaentry id="faq.programming.win32-api"> -<question><para>How do I use Win32 API calls?</para></question> -<answer> - -<para><emphasis role='bold'>(Please note: This section has not yet been updated for the latest net release.)</emphasis> -</para> -<para>It's pretty simple actually. Cygwin tools require that you explicitly -link the import libraries for whatever Win32 API functions that you -are going to use, with the exception of kernel32, which is linked -automatically (because the startup and/or built-in code uses it). -</para> -<para>For example, to use graphics functions (GDI) you must link -with gdi32 like this: -</para> -<para>gcc -o foo.exe foo.o bar.o -lgdi32 -</para> -<para>or (compiling and linking in one step): -</para> -<para>gcc -o foo.exe foo.c bar.c -lgdi32 -</para> -<para>The following libraries are available for use in this way: -</para> -<para>advapi32 largeint ole32 scrnsave vfw32 -cap lz32 oleaut32 shell32 win32spl -comctl32 mapi32 oledlg snmp winmm -comdlg32 mfcuia32 olepro32 svrapi winserve -ctl3d32 mgmtapi opengl32 tapi32 winspool -dlcapi mpr penwin32 th32 winstrm -gdi32 msacm32 pkpd32 thunk32 wow32 -glaux nddeapi rasapi32 url wsock32 -glu32 netapi32 rpcdce4 user32 wst -icmp odbc32 rpcndr uuid -imm32 odbccp32 rpcns4 vdmdbg -kernel32 oldnames rpcrt4 version -</para> -<para>The regular setup allows you to use the option -mwindows on the -command line to include a set of the basic libraries (and also -make your program a GUI program instead of a console program), -including user32, gdi32 and, IIRC, comdlg32. -</para> -<para>Note that you should never include -lkernel32 on your link line -unless you are invoking ld directly. Do not include the same import -library twice on your link line. Finally, it is a good idea to -put import libraries last on your link line, or at least after -all the object files and static libraries that reference them. -</para> -<para>The first two are related to problems the linker has (as of b18 at least) -when import libraries are referenced twice. Tables get messed up and -programs crash randomly. The last point has to do with the fact that -gcc processes the files listed on the command line in sequence and -will only resolve references to libraries if they are given after -the file that makes the reference. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.win32-no-cygwin"> -<question><para>How do I compile a Win32 executable that doesn't use Cygwin?</para></question> -<answer> - -<para>The -mno-cygwin flag to gcc makes gcc link against standard Microsoft -DLLs instead of Cygwin. This is desirable for native Windows programs -that don't need a UNIX emulation layer. -</para> -<para>This is not to be confused with 'MinGW' (Minimalist GNU for Windows), -which is a completely separate effort. That project's home page is -<ulink url="http://www.mingw.org/index.shtml">http://www.mingw.org/index.shtml</ulink>. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.static-linking"> -<question><para>Can I build a Cygwin program that does not require cygwin1.dll at runtime?</para></question> -<answer> - -<para>No. If your program uses the Cygwin API, then your executable cannot -run without cygwin1.dll. In particular, it is not possible to -statically link with a Cygwin library to obtain an independent, -self-contained executable. -</para> -<para>If this is an issue because you intend to distribute your Cygwin -application, then you had better read and understand -<ulink url="http://cygwin.com/licensing.html">http://cygwin.com/licensing.html</ulink>, which explains the licensing -options. Unless you purchase a special commercial license from Red -Hat, then your Cygwin application must be Open Source. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.msvcrt-and-cygwin"> -<question><para>Can I link with both MSVCRT*.DLL and cygwin1.dll?</para></question> -<answer> - -<para>No, you must use one or the other, they are mutually exclusive. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.no-console-window"> -<question><para>How do I make the console window go away?</para></question> -<answer> - -<para>The default during compilation is to produce a console application. -It you are writing a GUI program, you should either compile with --mwindows as explained above, or add the string -"-Wl,--subsystem,windows" to the GCC command line. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.make-spaces"> -<question><para>Why does make complain about a "missing separator"?</para></question> -<answer> - -<para>This problem usually occurs as a result of someone editing a Makefile -with a text editor that replaces tab characters with spaces. Command -lines must start with tabs. This is not specific to Cygwin. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.win32-headers"> -<question><para>Why can't we redistribute Microsoft's Win32 headers?</para></question> -<answer> - -<para>Subsection 2.d.f of the `Microsoft Open Tools License agreement' looks -like it says that one may not "permit further redistribution of the -Redistributables to their end users". We take this to mean that we can -give them to you, but you can't give them to anyone else, which is -something that we can't agree to. Fortunately, we -have our own Win32 headers which are pretty complete. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.msvs-mingw"> -<question><para>How do I use <literal>cygwin1.dll</literal> with Visual Studio or MinGW?</para></question> -<answer> - -<para>Before you begin, note that Cygwin is licensed under the GNU GPL (as -indeed are all other Cygwin-based libraries). That means that if your -code links against the cygwin dll (and if your program is calling -functions from Cygwin, it must, as a matter of fact, be linked against -it), you must apply the GPL to your source as well. Of course, this -only matters if you plan to distribute your program in binary form. For -more information, see <ulink url="http://gnu.org/licenses/gpl-faq.html">http://gnu.org/licenses/gpl-faq.html</ulink>. If -that is not a problem, read on. -</para> -<para>If you want to load the DLL dynamically, read -<literal>winsup/cygwin/how-cygtls-works.txt</literal> and the sample code in -<literal>winsup/testsuite/cygload</literal> to understand how this works. -The short version is: -</para> -<orderedlist><listitem><para>Make sure you have 4K of scratch space at the bottom of your stack. -</para></listitem> -<listitem><para>Invoke <literal>cygwin_dll_init()</literal>: -<screen> -HMODULE h = LoadLibrary("cygwin1.dll"); -void (*init)() = GetProcAddress(h, "cygwin_dll_init"); -init(); -</screen> -</para></listitem> -</orderedlist> - -<para>If you want to link statically from Visual Studio, to my knowledge -none of the Cygwin developers have done this, but we have this report -from the mailing list that it can be done this way: -</para> -<orderedlist><listitem><para>Use the impdef program to generate a .def file for the cygwin1.dll -(if you build the cygwin dll from source, you will already have a def -file) -</para> -<screen> -impdef cygwin1.dll > cygwin1.def -</screen> - -</listitem> -<listitem><para>Use the MS VS linker (lib) to generate an import library -</para> -<screen> -lib /def=cygwin1.def /out=cygwin1.lib -</screen> - -</listitem> -<listitem><para>Create a file "my_crt0.c" with the following contents -</para> -<screen> -#include <sys/cygwin.h> -#include <stdlib.h> - -typedef int (*MainFunc) (int argc, char *argv[], char **env); - -void - my_crt0 (MainFunc f) - { - cygwin_crt0(f); - } -</screen> - -</listitem> -<listitem><para>Use gcc in a Cygwin prompt to build my_crt0.c into a DLL - (e.g. my_crt0.dll). Follow steps 1 and 2 to generate .def and - .lib files for the DLL. -</para> -</listitem> -<listitem><para>Download crt0.c from the cygwin website and include it in - your sources. Modify it to call my_crt0() instead of - cygwin_crt0(). -</para> -</listitem> -<listitem><para>Build your object files using the MS VC compiler cl. -</para> -</listitem> -<listitem><para>Link your object files, cygwin1.lib, and my_crt0.lib (or - whatever you called it) into the executable. -</para></listitem> -</orderedlist> - -<para>Note that if you are using any other Cygwin based libraries -that you will probably need to build them as DLLs using gcc and -then generate import libraries for the MS VC linker. -</para> -<para>Thanks to Alastair Growcott (alastair dot growcott at bakbone dot co -dot uk) for this tip. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.linking-lib"> -<question><para>How do I link against a <literal>.lib</literal> file?</para></question> -<answer> - -<para>If your <literal>.lib</literal> file is a normal static or import library with -C-callable entry points, you can list <literal>foo.lib</literal> as an object file for -gcc/g++, just like any <literal>*.o</literal> file. Otherwise, here are some steps: -</para> -<orderedlist><listitem><para>Build a C file with a function table. Put all functions you intend -to use in that table. This forces the linker to include all the object -files from the .lib. Maybe there is an option to force LINK.EXE to -include an object file. -</para></listitem> -<listitem><para>Build a dummy 'LibMain'. -</para></listitem> -<listitem><para>Build a .def with all the exports you need. -</para></listitem> -<listitem><para>Link with your .lib using link.exe. -</para></listitem> -</orderedlist> - -<para>or -</para> -<orderedlist><listitem><para>Extract all the object files from the .lib using LIB.EXE. -</para></listitem> -<listitem><para>Build a dummy C file referencing all the functions you need, either - with a direct call or through an initialized function pointer. -</para></listitem> -<listitem><para>Build a dummy LibMain. -</para></listitem> -<listitem><para>Link all the objects with this file+LibMain. -</para></listitem> -<listitem><para>Write a .def. -</para></listitem> -<listitem><para>Link. -</para></listitem> -</orderedlist> - -<para>You can use these methods to use MSVC (and many other runtime libs) -with Cygwin development tools. -</para> -<para>Note that this is a lot of work (half a day or so), but much less than -rewriting the runtime library in question from specs... -</para> -<para>Thanks to Jacob Navia (root at jacob dot remcomp dot fr) for this explanation. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.building-cygwin"> -<question><para>How do I build Cygwin on my own?</para></question> -<answer> - -<para>First, you need to get the Cygwin source. Ideally, you should check out -what you need from CVS (<ulink url="http://cygwin.com/cvs.html">http://cygwin.com/cvs.html</ulink>). This is the -<emphasis>preferred method</emphasis> for acquiring the sources. Otherwise, you can -install the cygwin source package from the distribution. -</para> -<para>If you are trying to duplicate a cygwin release then you should just -download the corresponding source package and use "tar xjf" to unpack -it. This will unpack the sources into a directory named cygwin-x.y.z-n, -where x.y.z-n correspond to the version numbering of the tar.bz2 -package. -</para> -<screen> -tar xjf cygwin-1.5.12-1-src.tar.bz2 -cd cygwin-1.5.12-1 -</screen> - -<para>You <emphasis>must</emphasis> build cygwin in a separate directory from the source, -so create something like a <literal>build/</literal> directory. You will also want -to install to a temporary location: -</para> -<screen> -mkdir build -mkdir /install -cd build -(../configure --prefix=/install -v; make) >& make.out -make install > install.log 2>&1 -</screen> - -<para>Normally, this procedure ignore errors in building the documentation. -which requires the <literal>docbook-xml</literal>, <literal>docbook-xsl</literal>, and -<literal>xmlto</literal> packages. For more information on building the -documentation, see the README included in the cygwin-doc package. -</para> -<para>To check a cygwin1.dll, run "make check" in the winsup/testsuite -directory. If that works, install everything <emphasis>except</emphasis> the dll (if -you can). Then, close down all cygwin programs (including bash windows, -inetd, etc.), save your old dll, and copy the new dll to the correct -place. Then start up a bash window, or run a cygwin program from the -Windows command prompt, and see what happens. -</para> -<para>If you get the error "shared region is corrupted" it means that two -different versions of cygwin1.dll are running on your machine at the -same time. Remove all but one. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.debugging-cygwin"> -<question><para>I may have found a bug in Cygwin, how can I debug it (the symbols in gdb look funny)?</para></question> -<answer> - -<para>Debugging symbols are stripped from distibuted Cygwin binaries, so any -symbols that you see in gdb are basically meaningless. It is also a good -idea to use the latest code in case the bug has been fixed, so we -recommend trying the latest snapshot from -<ulink url="http://cygwin.com/snapshots/" /> or building the DLL from CVS. -</para> -<para>To build a debugging version of the Cygwin DLL, you will need to follow -the instructions at <ulink url="http://cygwin.com/faq/faq-nochunks.html#faq.programming.building-cygwin" />. -You can also contact the mailing list for pointers (a simple test case that -demonstrates the bug is always welcome). -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.compiling-unsupported"> -<question><para>How can I compile Cygwin for an unsupported platform (PowerPC, Alpha, ARM, Itanium)?</para></question> -<answer> - -<para>Unfortunately, this will be difficult. Exception handling and signals -support semantics and args have been designed for x86 so you would need -to write specific support for your platform. We don't know of any other -incompatibilities. Please send us patches if you do this work! -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.adjusting-heap"> -<question><para>How can I adjust the heap/stack size of an application?</para></question> -<answer> - -<para>If you need to change the maximum amount of memory available to Cygwin, see -<ulink url="http://cygwin.com/cygwin-ug-net/setup-maxmem.html">http://cygwin.com/cygwin-ug-net/setup-maxmem.html</ulink>. Otherwise, -just pass heap/stack linker arguments to gcc. To create foo.exe with -a heap size of 1024 and a stack size of 4096, you would invoke -gcc as: -</para> -<para><literal>gcc -Wl,--heap,1024,--stack,4096 -o foo foo.c</literal> -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.dll-cygcheck"> -<question><para>How can I find out which DLLs are needed by an executable?</para></question> -<answer> - -<para><literal>objdump -p</literal> provides this information, but is rather verbose. -</para> -<para><literal>cygcheck</literal> will do this much more concisely, and operates -recursively, provided the command is in your path. -</para> -<para>Note there is currently a bug in cygcheck in that it will not report -on a program in a Windows system dir (e.g., C:\Windows or C:\WINNT) even -if it's in your path. To work around this, supply the full Win32 path -to the executable, including the .exe extension: -</para> -<screen> -cygcheck c:\\winnt\\system32\\cmd.exe -</screen> - -<para>(Note the windows path separator must be escaped if this is typed in -bash.) -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.dll-building"> -<question><para>How do I build a DLL?</para></question> -<answer> - -<para>There's documentation that explains the process in the Cygwin User's -Guide here: <ulink url="http://cygwin.com/cygwin-ug-net/dll.html">http://cygwin.com/cygwin-ug-net/dll.html</ulink> -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.breakpoint"> -<question><para>How can I set a breakpoint at MainCRTStartup?</para></question> -<answer> - -<para><emphasis role='bold'>(Please note: This section has not yet been updated for the latest net release.)</emphasis> -</para> -<para>Set a breakpoint at *0x401000 in gdb and then run the program in -question. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.dll-relocatable"> -<question><para>How can I build a relocatable dll?</para></question> -<answer> - -<para><emphasis role='bold'>(Please note: This section has not yet been updated for the latest net release. However, there was a discussion on the cygwin mailing list recently that addresses this issue. Read <ulink url="http://cygwin.com/ml/cygwin/2000-06/msg00688.html">http://cygwin.com/ml/cygwin/2000-06/msg00688.html</ulink> and related messages.)</emphasis> -</para> -<para>You must execute the following sequence of five commands, in this -order: -</para> -<screen> -$(LD) -s --base-file BASEFILE --dll -o DLLNAME OBJS LIBS -e ENTRY - -$(DLLTOOL) --as=$(AS) --dllname DLLNAME --def DEFFILE \ - --base-file BASEFILE --output-exp EXPFILE - -$(LD) -s --base-file BASEFILE EXPFILE -dll -o DLLNAME OBJS LIBS -e ENTRY - -$(DLLTOOL) --as=$(AS) --dllname DLLNAME --def DEFFILE \ - --base-file BASEFILE --output-exp EXPFILE - -$(LD) EXPFILE --dll -o DLLNAME OBJS LIBS -e ENTRY -</screen> - -<para>In this example, $(LD) is the linker, ld. -</para> -<para>$(DLLTOOL) is dlltool. -</para> -<para>$(AS) is the assembler, as. -</para> -<para>DLLNAME is the name of the DLL you want to create, e.g., tcl80.dll. -</para> -<para>OBJS is the list of object files you want to put into the DLL. -</para> -<para>LIBS is the list of libraries you want to link the DLL against. For -example, you may or may not want -lcygwin. You may want -lkernel32. -Tcl links against -lcygwin -ladvapi32 -luser32 -lgdi32 -lcomdlg32 --lkernel32. -</para> -<para>DEFFILE is the name of your definitions file. A simple DEFFILE would -consist of ``EXPORTS'' followed by a list of all symbols which should -be exported from the DLL. Each symbol should be on a line by itself. -Other programs will only be able to access the listed symbols. -</para> -<para>BASEFILE is a temporary file that is used during this five stage -process, e.g., tcl.base. -</para> -<para>EXPFILE is another temporary file, e.g., tcl.exp. -</para> -<para>ENTRY is the name of the function which you want to use as the entry -point. This function should be defined using the WINAPI attribute, -and should take three arguments: - int WINAPI startup (HINSTANCE, DWORD, LPVOID) -</para> -<para>This means that the actual symbol name will have an appended @12, so if -your entry point really is named <literal>startup</literal>, the string you should -use for ENTRY in the above examples would be <literal>startup@12</literal>. -</para> -<para>If your DLL calls any Cygwin API functions, the entry function will need -to initialize the Cygwin impure pointer. You can do that by declaring -a global variable <literal>_impure_ptr</literal>, and then initializing it in the -entry function. Be careful not to export the global variable -<literal>_impure_ptr</literal> from your DLL; that is, do not put it in DEFFILE. -</para> -<screen> -/* This is a global variable. */ -struct _reent *_impure_ptr; -extern struct _reent *__imp_reent_data; - -int entry (HINSTANT hinst, DWORD reason, LPVOID reserved) -{ - _impure_ptr = __imp_reent_data; - /* Whatever else you want to do. */ -} -</screen> - -<para>You may put an optional `--subsystem windows' on the $(LD) lines. The -Tcl build does this, but I admit that I no longer remember whether -this is important. Note that if you specify a --subsytem <x> flag to ld, -the -e entry must come after the subsystem flag, since the subsystem flag -sets a different default entry point. -</para> -<para>You may put an optional `--image-base BASEADDR' on the $(LD) lines. -This will set the default image base. Programs using this DLL will -start up a bit faster if each DLL occupies a different portion of the -address space. Each DLL starts at the image base, and continues for -whatever size it occupies. -</para> -<para>Now that you've built your DLL, you may want to build a library so -that other programs can link against it. This is not required: you -could always use the DLL via LoadLibrary. However, if you want to be -able to link directly against the DLL, you need to create a library. -Do that like this: -</para> -<para>$(DLLTOOL) --as=$(AS) --dllname DLLNAME --def DEFFILE --output-lib LIBFILE -</para> -<para>$(DLLTOOL), $(AS), DLLNAME, and DEFFILE are the same as above. Make -sure you use the same DLLNAME and DEFFILE, or things won't work right. -</para> -<para>LIBFILE is the name of the library you want to create, e.g., -libtcl80.a. You can then link against that library using something -like -ltcl80 in your linker command. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.debug"> -<question><para>How can I debug what's going on?</para></question> -<answer> - -<para>You can debug your application using <literal>gdb</literal>. Make sure you -compile it with the -g flag! If your application calls functions in -MS DLLs, gdb will complain about not being able to load debug information -for them when you run your program. This is normal since these DLLs -don't contain debugging information (and even if they did, that debug -info would not be compatible with gdb). -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.system-trace"> -<question><para>Can I use a system trace mechanism instead?</para></question> -<answer> - -<para>Yes. You can use the <literal>strace.exe</literal> utility to run other cygwin -programs with various debug and trace messages enabled. For information -on using <literal>strace</literal>, see the Cygwin User's Guide or the file -<literal>winsup/utils/utils.sgml</literal>. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.gdb-signals"> -<question><para>Why doesn't gdb handle signals?</para></question> -<answer> - -<para>Unfortunately, there is only minimal signal handling support in gdb -currently. Signal handling only works with Windows-type signals. -SIGINT may work, SIGFPE may work, SIGSEGV definitely does. You cannot -'stop', 'print' or 'nopass' signals like SIGUSR1 or SIGHUP to the -process being debugged. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.linker"> -<question><para>The linker complains that it can't find something.</para></question> -<answer> - -<para>A common error is to put the library on the command line before -the thing that needs things from it. -</para> -<para>This is wrong <literal>gcc -lstdc++ hello.cc</literal>. -This is right <literal>gcc hello.cc -lstdc++</literal>. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.undeclared-functions"> -<question><para>I use a function I know is in the API, but I still get a link error.</para></question> -<answer> - -<para>The function probably isn't declared in the header files, or -the UNICODE stuff for it isn't filled in. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.libc"> -<question><para>Can you make DLLs that are linked against libc ?</para></question> -<answer> - -<para>Yes. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.malloc-h"> -<question><para>Where is malloc.h?</para></question> -<answer> - -<para><emphasis role='bold'>(Please note: This section has not yet been updated for the latest net release.)</emphasis> -</para> -<para>Include stdlib.h instead of malloc.h. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.own-malloc"> -<question><para>Can I use my own malloc?</para></question> -<answer> - -<para>If you define a function called <literal>malloc</literal> in your own code, and link -with the DLL, the DLL <emphasis>will</emphasis> call your <literal>malloc</literal>. Needless to -say, you will run into serious problems if your malloc is buggy. -</para> -<para>If you run any programs from the DOS command prompt, rather than from in -bash, the DLL will try and expand the wildcards on the command line. -This process uses <literal>malloc</literal> <emphasis>before</emphasis> your main line is started. -If you have written your own <literal>malloc</literal> to need some initialization -to occur after <literal>main</literal> is called, then this will surely break. -</para> -<para>Moreover, there is an outstanding issue with <literal>_malloc_r</literal> in -<literal>newlib</literal>. This re-entrant version of <literal>malloc</literal> will be called -directly from within <literal>newlib</literal>, by-passing your custom version, and -is probably incompatible with it. But it may not be possible to replace -<literal>_malloc_r</literal> too, because <literal>cygwin1.dll</literal> does not export it and -Cygwin does not expect your program to replace it. This is really a -newlib issue, but we are open to suggestions on how to deal with it. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.msvc-gcc-objects"> -<question><para>Can I mix objects compiled with msvc++ and gcc?</para></question> -<answer> - -<para>Yes, but only if you are combining C object files. MSVC C++ uses a -different mangling scheme than GNU C++, so you will have difficulties -combining C++ objects. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.gdb-msvc"> -<question><para>Can I use the gdb debugger to debug programs built by VC++?</para></question> -<answer> - -<para>No, not for full (high level source language) debugging. -The Microsoft compilers generate a different type of debugging -symbol information, which gdb does not understand. -</para> -<para>However, the low-level (assembly-type) symbols generated by -Microsoft compilers are coff, which gdb DOES understand. -Therefore you should at least be able to see all of your -global symbols; you just won't have any information about -data types, line numbers, local variables etc. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.x86-assembly"> -<question><para>Where can I find info on x86 assembly?</para></question> -<answer> - -<para>CPU reference manuals for Intel's current chips are available in -downloadable PDF form on Intel's web site: -</para> -<para><ulink url="http://developer.intel.com/design/pro/manuals/">http://developer.intel.com/design/pro/manuals/</ulink> -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.make-scripts"> -<question><para>Shell scripts aren't running properly from my makefiles?</para></question> -<answer> - -<para>If your scripts are in the current directory, you must have <literal>.</literal> -(dot) in your $PATH. (It is not normally there by default.) Otherwise, -you would need to add /bin/sh in front of each and every shell script -invoked in your Makefiles. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.preprocessor"> -<question><para>What preprocessor do I need to know about?</para></question> -<answer> - -<para>We use _WIN32 to signify access to the Win32 API and __CYGWIN__ for -access to the Cygwin environment provided by the dll. -</para> -<para>We chose _WIN32 because this is what Microsoft defines in VC++ and -we thought it would be a good idea for compatibility with VC++ code -to follow their example. We use _MFC_VER to indicate code that should -be compiled with VC++. -</para> -<para>_WIN32 is only defined when you use either the -mno-cygwin or -mwin32 -gcc command line options. This is because Cygwin is supposed to be a -Unix emulation environment and defining _WIN32 confuses some programs -which think that they have to make special concessions for a Windows -environment which Cygwin handles automatically. -</para> -<para>Note that using -mno-cygwin replaces __CYGWIN__ with __MINGW32__ as to -tell which compiler (or settings) you're running. -Check this out in detail by running, for example -</para> -<screen> - $ gcc -dM -E -xc /dev/null >gcc.txt - $ gcc -mno-cygwin -dM -E -xc /dev/null >gcc-mno-cygwin.txt - $ gcc -mwin32 -dM -E -xc /dev/null >gcc-mwin32.txt -</screen> -<para>Then use the diff and grep utilities to check -what the difference is. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.unix-gui"> -<question><para>How should I port my Unix GUI to Windows?</para></question> -<answer> - -<para>There are two basic strategies for porting Unix GUIs to Windows. -</para> -<para>The first is to use a portable graphics library such as tcl/tk, X11, or -V (and others?). Typically, you will end up with a GUI on Windows that -requires some runtime support. With tcl/tk, you'll want to include the -necessary library files and the tcl/tk DLLs. In the case of X11, you'll -need everyone using your program to have an X11 server installed. -</para> -<para>The second method is to rewrite your GUI using Win32 API calls (or MFC -with VC++). If your program is written in a fairly modular fashion, you -may still want to use Cygwin if your program contains a lot of shared -(non-GUI-related) code. That way you still gain some of the portability -advantages inherent in using Cygwin. -</para> -</answer></qandaentry> - -<qandaentry id="faq.programming.djgpp"> -<question><para>Why not use DJGPP ?</para></question> -<answer> - -<para>DJGPP is a similar idea, but for DOS instead of Win32. DJGPP uses a -"DOS extender" to provide a more reasonable operating interface for its -applications. The Cygwin toolset doesn't have to do this since all of -the applications are native WIN32. Applications compiled with the -Cygwin tools can access the Win32 API functions, so you can write -programs which use the Windows GUI. -</para> -<para>You can get more info on DJGPP by following -<ulink url="http://www.delorie.com/">http://www.delorie.com/</ulink>. -</para></answer></qandaentry> - |