Q: What's the minimum set of .zip files I need for compiling programs? A: djeoeXXX, djdevXXX, gccXXXbn, gasXXXbn, and bnuXXbn are required. The remainder are for additional functionality. Note that the version numbers do not neccessarily match between FSF programs (gas and gcc) and my programs (go32). You'll also need bsnXXXbn for bison and flxXXXbn for flex, where XXX is the version number. Note that C++ requires gppXXX.zip, and ObjectiveC requires objcXXX.zip. The C++ library includes obstacks, alloca, and regex, so you need to get gppXXX.zip to use them (libgpl.a) Q: I need 1.12.maint1! A: Get and install dj112m1.zip (and dj112m2.zip, etc). These are maintainence releases, and include updates to go32 and other programs. They should be installed in order and after all other modules. Q: What about documentation? A: Get txiXXX.bn, which includes INFO.EXE. Unpack it and run "info". It will bring up a (hopefully) self-explanatory online help system. For go32 and programs I wrote, get djdocXXX.zip, which includes the data files for the online help system. For the FSF utilities, djgpp includes three files each. Example: gcc257bn.zip - binaries & source diffs for gcc 2.5.7 gcc257dc.zip - documentation for gcc 2.5.7 gcc257sr.zip - original FSF sources for gcc 2.5.7 (Some sources are too big, and are split into multiple zips, all of which must be unzipped to get a complete source distribution: gcc257s1.zip gcc257s2.zip gcc257s3.zip All sources are shipped in ready-to-build form. The diffs in the diffs directory have already been applied.) Q: How do I find out what go32 is doing? A: The first thing to do is run "go32". It will give you gobs of information about what it knows about your system and itself. Next, set the "topline" flag in the GO32 environment varable (see the README) and watch the top line of your screen. The info there tells you something about what the program is doing. Q: I get errors I can't figure out when I try to compile something. A: The best way to figure out what's going wrong with gcc is to use the "-v" switch. For example, if you run "gcc -v hello.c" (assuming you have hello.c), it will tell you all the programs it is running. Then, you can see which program caused the error. The most likely cause of errors relating to missing programs is that you haven't unpacked the zip file with one of the compiler passes or utilities on it. Q: Why do I get so many unresolved symbols when linking C++ programs? A: The C++ libraries are not in libc.a, which is the only default library. You must use a command like this: gcc -o prog prog.o -lgpp -lm Note that some C++ classes use math routines, so the -lm should be given after the -lgplus. If you don't link with -lgpl or -lgpp, you won't include any GPL code in your application. You may not need all of these libraries for your program. Q: How do I debug my programs? A: First, remember to use the -g switch when you compile. This puts debugging information into your executable. Then, to debug the program, use a command line like this: go32 -d edebug32 myprog "edebug32" is the external debugger. See the file "edebug32.doc" for information on the debugger commands. Note: if you are running in a DPMI environment, you must use "ed32-dpmi" instead of "edebug32". Go32 normally searches relative to the current directory, then from it's own directory, then the PATH, for the external debugger program. Q: When I run my programs under Windows, they crash, but not outside of Windows. A: You may have used the "-fomit-frame-pointer" option to GCC. This tells gcc that it can use EBP as a general register. However, the segment used for the stack is protected against access outside of calculated stack range, and EBP causes the stack selector to be used. If you use this to access memory in the regular data area, you get a protection fault. This mechanism is present to prevent you from using so much stack that you begin corrupting data. Outside of Windows, a different method is used to detect stack overrun, so you don't see this fault. Q: How do I create symbolic links? A: Copy bin/stub.exe to the name of the link you want. In this example, let's say the real program is dj1.exe and we want to make a link called dj2.exe that really calls dj1.exe. We'd copy stub.exe to dj2.exe. Next, run stubedit to modify the new programs' stub info block to change the name of the executable it runs. In this case, we'd change it to dj1. When you run dj2 now, it tells go32 to use the image of dj1. C:\> copy c:\djgpp\bin\stub.exe c:\usr\bin\dj2.exe C:\> stubedit c:/usr/bin/dj2.exe runfile=dj1 Q: When I run "gcc e:\proj\prog.c" it says "undefined escape sequence \p"? A: Gcc is a *unix* compiler - you must use *unix* slashes (e:/proj/prog.c). Environment variables (like GCCINC) may, however, use either, as they are converted. Q: I type "GCC PROG.C" and ld complains about PROG.C not being an object. Q: I type "gcc prog.cxx" to compile a C++ program, and ld complains. A: Gcc is *not* case insensitive like DOS is, and it uses the file's extension to determine how to compile a file. Valid extensions are: .cc = C++ source (passed through cpp) .c = C source that must be passed through cpp first .i = raw C source (no cpp pass) .S = assembler that must be passed through cpp first .s = raw assembler source (no cpp pass) any other file is passed to the linker Q: I compile my program, but can't run the output file. A: DOS doesn't know how to run unix-style COFF files. That's what the extender is for. To run an COFF file called myprog, type "go32 myprog . . ." Q: I compile my program, but when I run the .exe it hangs. A: Most likely, you did this: "gcc foo.c -o foo.exe". This doesn't create a real .EXE file. That's like renaming your phone directory file to an .EXE and expecting it to run. You must use the COFF2EXE program to convert the output of gcc to a real executable. Q: Gcc doesn't recognize // as a comment in my C programs. A: That's because // isn't a comment in C. If you want to compile C++, then write C++ programs. Gcc is really two compilers in one, not one compiler that compiles both C and C++. That's why you get cc1 and cc1plus. Q: I'm reading in data files, but the data gets corrupted. A: The default file type is DOS text, even for read() and write(). You must tell the system that a file is binary through the "b" flag in fopen(), or O_BINARY in open() or setmode(). Q: I get "fatal signal 2" when I run gcc. A: When gcc reports a "signal", it really means that an error occurred trying to run the given program. The "signal" number is the DOS error code, and 2 means "file not found". Check the COMPILER_PATH environment variable and make sure it points to the directory with cpp.exe, cc1.exe, etc. Q: The binaries I get with the distribution are .exe files, but gcc creates COFF files. I rename the COFF's to .EXE's, but they still don't work. A: To get an .EXE from an COFF, you must *prepend* either go32.exe or stub.exe to the file. A program called "coff2exe" is provided to do this. Just run "coff2exe myprog". Q: What is stub.exe? A: Stub.exe simply calles go32.exe, and passes it information it needs to run the COFF file attached to it. Stub is much smaller than go32, so less disk space is used. Also, if you change go32, you don't have to change stub, and all the stub-ized programs will use the new go32 automatically. Q: I want to change cc1. How do I do this? A: First, get the GNU sources. These should be the "gccXXXsr.zip" files found in the djgpp distribution. You can also get the latest versions from the FSF if you like. They're usually available at prep.ai.mit.edu in /pub/gnu, if not elsewhere. djgpp includes a copy of gzip (gzp124bn.zip) that can uncompress them. Use djtarx to un-tar them, as djtarx knows how to handle unix file names that aren't valid DOS file names. Next, apply the "diffs" (if any) over the GNU sources (making sure you have the right version of GNU - see the versions file). For most GNU utilities, you must run "configure" to prepare the sources for a native go32 build before building. For all other programs, just run make. Note that the makefiles are tuned for gnu make, since it knows how to handle long command lines. Specific instructions are documented in the diffs or in each program's configure.bat. Q: I don't have an 80387. How do I compile floating point programs? A: Add "emu c:\djgpp\bin\emu387" to the GO32 environment variable (see go32 section in readme). This tells go32 to use the given file as an 80387 emulator. If you don't load this emulator, and you try to run floating point without a 387, you will get an error. Q: I installed an 80387 emulator in my AUTOEXEC, but it still doesn't work. Why? A: The CPU is running in *protected* mode, not real mode, and the information needed to emulate the 80387 is different. Not to mention that the exceptions never get to the real-mode handler. You must use the emu387 emulator, which is designed for go32. Q: Can I run this on my 286? It has protected mode also... A: True, but the 286 isn't a 32-bit processor. A 386 really is required. Q: Can I use gcc on my 512K machine? A: Yes, but the disk better have at least 4Mb of free space for paging. Go32 will use all available extended memory (up to 128M) and up to 128M of disk space, for a grand total of 256M of virtual memory for your application. Try a malloc(50*1024*1024) some day. Q: Why do my compiles are running VERY SLOW, even though I use a ramdisk for swap and a disk cache? A: Gcc requires at least 1Mb of virtual memory to run, usually close to 1.5M. If there isn't this much real memory available, it starts paging to disk. It's good to leave about 1M of extended (or expanded) memory available for go32 to run programs with. When it needs to page a lot, you spend most of your time paging and little time actually running. Note that if you are running with a VCPI server, like QEMM or 386MAX, then go32 will use *expanded* memory for it's physical memory needs, not extended. If you are redirecting your swap to a ramdisk, you'd be better off turning that memory back into extended (or expanded) memory for go32 to use better. Q: How much memory is available when I use the system() call? A: Everything but what go32 is loaded with. The program is completely paged out to memory (including the page tables themselves) before the second program is executed. Currently, this is about 130K less than was available before go32 was executed, since go32 itself remains in memory. Q: Go32 complains that the CPU must be in V86 mode to run. A: When the CPU is in V86 mode, the V86 manager must provide VCPI services for go32. Since VCPI is an extension to EMS, disabling EMS will disable VCPI, and prevent go32 from running. For some EMS managers, this means that you can't use the "noems" switch. Q: Why can't I keep QEMM in auto/off mode? A: When QEMM is in auto/off mode and there isn't anything in the system that is using any of QEMM's features, the CPU remains in "real" mode. Go32 knows this, and will try to use XMS to access the extended memory. Unfortunately, XMS is a feature that causes QEMM to turn on, and go32 doesn't know this and when it tries to switch into protected mode, QEMM traps it and gives a protection violation warning. Since this always requires a system reboot to fix, go32 checks to see if enabling XMS caused the cpu to switch into v86 mode (meaning QEMM just turned on) and gracefully exits. All you have to do to work around this is force QEMM to be on all the time so that go32 will know how to work with it properly. Q: How do globbing and response files work? A: A response file is a file that contains stuff that goes on the command line, but is too big for DOS. The name of the file is given as "@file" to any COFF program, and go32 reads the file for command line information. It uses single and double quotes to group parameters, and backslashes to escape quotes, spaces, tabs, newlines, and backslashes. Parameters containing wildcards are expanded if they can be, else they are unmodified. Surrounding a parameter in single quotes will prevent wildcards from being expanded. This is similar to unix. Note that backslashes are not special if they are not in front of a quote, whitespace, or backslash. Q: What is GCC-RM? How do I use it? A: GCC is merely a driver program which calls the CCP, CC1, AS, LD images. The real-mode gcc is simply gcc itself compiled with Turbo-C instead of Gcc. This improves compile times on most systems, but isn't as "clean" as the 32-bit compiled version, and also the 32-bit version can be recompiled (FSF desires) without having to purchase a new compiler. Both versions should produce exactly the same output, but if you have any problems (such as under Novell) use the 32 bit version. You can either put GCC-RM in your path and issue GCC as your compile command, or copy it to the bin directory (saving the 32 bit GCC.EXE first). GCC-RM does not create 16 bit code, or allow the compiler to work on 16 bit only machines. Q: Is GDB available for DJGPP? A: Yes, see gdbXXXbn.zip. Note that it doesn't work exactly like the Unix versions. For example, you can't pass command line parameters to gdb, and you can only start the program once. Q: Where is the "make" utility? A: makXXXbn.zip contains the make utility. Q: Why can't I get segment registers to work in go32 programs? A: Because segments work differently in protected mode. For most cases, you will not need to use segments. The "small" model allows up to 2 Gb of data space before you run out, so there's no need for far pointers anyway.