Like any Nix distribution, the Cygwin 64 emulator allows running 32 bit executables (as long as they are compatible). You only need to either have:
- The right packages installed
- The right .dlls in the right place (as you mentioned) - but manually copying them (especially in system locations) is neither scalable, nor does it guarantee that the system will properly work afterwards
First, you'd need the cygwin32 package (at least) installed:
Since I don't have your 32 bit executable (I didn't fell like searching downloading, unpacking, and so on ...), I created a small example (to make it run, you'd need the gcc toolchains as well - which I have for other purposes, but anyway this is not related to the question) that reproduces the behavior.
code.c:
#include <stdio.h>
int main() {
printf(""void*" is %d bits long.
", sizeof(void*) * 8);
return 0;
}
Output:
[cfati@cfati-5510-0:/cygdrive/e/Work/Dev/StackOverflow/q054206577]> ~/sopr.sh
### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###
[064bit prompt]> uname -a
CYGWIN_NT-10.0 cfati-5510-0 2.11.2(0.329/5/3) 2018-11-08 14:34 x86_64 Cygwin
[064bit prompt]> ls
code.c
[064bit prompt]> x86_64-pc-cygwin-gcc.exe -o exe-gcc-064.exe code.c
[064bit prompt]> i686-pc-cygwin-gcc.exe -o exe-gcc-032.exe code.c -m32
[064bit prompt]> ls -al
total 433
drwxrwx---+ 1 Administrators None 0 Jan 16 12:45 .
drwxrwx---+ 1 Administrators None 0 Jan 16 10:33 ..
-rwxrwx---+ 1 Administrators None 118 Jan 16 10:39 code.c
-rwxrwxr-x+ 1 cfati None 151062 Jan 16 12:45 exe-gcc-032.exe
-rwxrwxr-x+ 1 cfati None 157755 Jan 16 12:45 exe-gcc-064.exe
[064bit prompt]>
[064bit prompt]> file exe-gcc-064.exe
exe-gcc-064.exe: PE32+ executable (console) x86-64, for MS Windows
[064bit prompt]> ldd exe-gcc-064.exe
ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffcaf990000)
KERNEL32.DLL => /cygdrive/c/WINDOWS/System32/KERNEL32.DLL (0x7ffcaf300000)
KERNELBASE.dll => /cygdrive/c/WINDOWS/System32/KERNELBASE.dll (0x7ffcabe60000)
cygwin1.dll => /usr/bin/cygwin1.dll (0x180040000)
[064bit prompt]> ./exe-gcc-064.exe
"void*" is 64 bits long.
[064bit prompt]>
[064bit prompt]> file exe-gcc-032.exe
exe-gcc-032.exe: PE32 executable (console) Intel 80386, for MS Windows
[064bit prompt]> ldd exe-gcc-032.exe
ntdll.dll => /cygdrive/c/WINDOWS/SYSTEM32/ntdll.dll (0x7ffcaf990000)
??? => ??? (0x77150000)
wow64.dll => /cygdrive/c/WINDOWS/System32/wow64.dll (0x7ffcaf800000)
wow64win.dll => /cygdrive/c/WINDOWS/System32/wow64win.dll (0x7ffcad570000)
[064bit prompt]> ./exe-gcc-032.exe
[064bit prompt]>
[064bit prompt]> echo $?
127
As you can see, I ran into the exact same problem for exe-gcc-032.exe. The ??? dependency is the 32 bit cygwin1.dll. Let's explore the problem:
[064bit prompt]> find /usr -name cygwin1.dll
/usr/i686-pc-cygwin/sys-root/usr/bin/cygwin1.dll
/usr/bin/cygwin1.dll
[064bit prompt]> cygcheck -f /usr/bin/cygwin1.dll
cygwin-2.11.2-1
[064bit prompt]> file /usr/bin/cygwin1.dll
/usr/bin/cygwin1.dll: PE32+ executable (DLL) (console) x86-64, for MS Windows
[064bit prompt]>
[064bit prompt]> cygcheck -f /usr/i686-pc-cygwin/sys-root/usr/bin/cygwin1.dll
cygwin32-2.10.0-1
[064bit prompt]> file /usr/i686-pc-cygwin/sys-root/usr/bin/cygwin1.dll
/usr/i686-pc-cygwin/sys-root/usr/bin/cygwin1.dll: PE32 executable (DLL) (console) Intel 80386 (stripped to external PDB), for MS Windows
[064bit prompt]>
[064bit prompt]> echo ${PATH}
/usr/local/bin:/usr/bin:/cygdrive/c/Program Files (x86)/Common Files/Oracle/Java/javapath:/cygdrive/c/WINDOWS/system32:/cygdrive/c/WINDOWS:/cygdrive/c/WINDOWS/System32/Wbem:/cygdrive/c/WINDOWS/System32/>WindowsPowerShell/v1.0:/cygdrive/c/Install/x64/NVidia/GPU Computing Toolkit/CUDA/AllVers/bin:/cygdrive/c/Install/x64/NVidia/GPU Computing Toolkit/CUDA/AllVers/libnvvp:/cygdrive/c/Install/x86/Borland/Del>phi/7/>Bin:/cygdrive/c/Install/x86/Borland/Delphi/7/Projects/Bpl:/cygdrive/c/ProgramData/Oracle/Java/javapath:/cygdrive/c/Program Files (x86)/Intel/iCLS Client:/cygdrive/c/Program Files/Intel/iCLS Client:/cygd>rive/c/>Program Files (x86)/Intel/Intel(R) Management Engine Components/DAL:/cygdrive/c/Program Files/Intel/Intel(R) Management Engine Components/DAL:/cygdrive/c/Program Files (x86)/Intel/Intel(R) Management En>gine >Components/IPT:/cygdrive/c/Program Files/Intel/Intel(R) Management Engine Components/IPT:/cygdrive/c/Program Files (x86)/NVIDIA Corporation/PhysX/Common:/cygdrive/c/WINDOWS/System32/OpenSSH:/cygdrive/c/>Insta>ll/>x86/IVI Foundation/VISA/AllVers/WinNT/Bin:/cygdrive/c/Program Files/IVI Foundation/VISA/Win64/Bin:/cygdrive/c/Install/x86/IVI Foundation/VISA/AllVers/WinNT/Bin:/cygdrive/e/Work/Dev/Utils/cfati-5510-0/>windows:/cygdrive/c/Install/x64/NVidia/GPU Computing Toolkit/cuDNN/AllVers/bin:/cygdrive/c/Users/cfati/AppData/Local/Microsoft/WindowsApps:/cygdrive/c/Install/Qt/Qt/5.9.1/msvc2015/bin
So, the 32 bit .dll exists (installed by the above package), but it can't be found, as its dir is not in ${PATH} (due to the content length this isn't immediately visible). Note that Cygwin doesn't honour LD_LIBRARY_PATH in this scenario.
The obvious step is to let the system know about this .dll, by adding its dir in PATH (at the beginning):
[064bit prompt]> export PATH=/usr/i686-pc-cygwin/sys-root/usr/bin:${PATH}
[064bit prompt]> ./exe-gcc-032.exe
"void*" is 32 bits long.
[064bit prompt]> ./exe-gcc-064.exe
"void*" is 64 bits long.
There you go.
Final notes:
- (64 bit) ldd which is an .exe (unlike on Nix, where it's a script), doesn't gracefully handle dependencies for 32 bit artefacts. Unfortunately, cygwin32-binutils package doesn't provide a 32 bit counterpart that wouldn't have this problem, so at the current moment this is as good as it gets
- You might run into some issues when running your .exe, because of possible differences between cygwin1.dll versions (the one that rxvt-native.exe expects, and the one present on the system). If so, I'd suggest that you start your Cygwin 32 environment, get the cygwin package version (let's call it CYGWIN_PKG_VER), and on the Cygwin 64t environment, install the cygwin32 version that is closest to %CYGWIN_PKG_VER%
Update #0
I added system("echo ${PATH}"); (and implicitly #include <stdlib.h>) in my test program, and on the 32 bit variant, system returned 127 (just like exe-gcc-032.exe's exit code when not having the proper path). I suspect the 2 can't be unrelated, and something happens with the environment, when launching 32 bit applications, and probably rxvt-native tries to launch bash (or any other command) via system.
Update #1
So, it is possible to run a 32 bit application from Cygwin 64 (a brief check, didn't reveal any official sources stating that it's an Unsupported Configuration). But in this particular case, since the app is complex (it's a terminal, required to run multiple other applications), there is a problem. Possible ways (some suggested by other people) to go further:
- Time to let go (probably there is a good reason why it wasn't ported). Switch to a modern replacement (Mintty)
- Search for an unofficial prebuilt 64 bit version of rxvt, or try building it yourself (there are some other people who like it)
- Have both environments (Cygwin 32 and Cygwin 64) installed on your PC
- Use your favorite terminal (from Cygwin 32). This will be your "main" environment
- Administrate Cygwin 64 "remotely", e.g. via:
- ssh: I didn't check for restrictions regarding the 2 sshds running in parallel on the same machine, but if there aren't any, you should change the listening port from default (22) for one of them. I'd suggest to do that for the former, so that the latter is available from "outside" using default settings
- Continue research on this direction, but as I see things, it's starting (if it hasn't already) to become a card castle - this seems more like a workaround (gainarie)
