impossible to link a dll with libcygipc

[Reini Urban]

please ask support questions at the cygwin list! this is just for blabbeling

gilles schrieb:
> Hello
> I encountered a little problem (which I 'd resolved few months ago but I 
> changed of environment and it does
> not work any more)
> I am compiling a little "helloworld" program that uses ipc APIs (cygipc) and  I 
> make it a dll (for JNI/JAVA purposes)
>  
> At link time , gcc can not found msget call !
> I checked that the libcygipc.a static library is right located 
> (/cygdrive/c/cygwin/lib)
>  
> Command is : 
> gcc   -Wl,--add-stdcall-alias -shared -lcygipc -o Native.dll  HelloWorld.c
> /cygdrive/c/Temp/ccnPWqb4.o(.text+0x7d):HelloWorld.c:
>  undefined reference to `msgget'
> collect2: ld returned 1 exit status
>  
>  
> On another configuration, Another similar, but more tricky "bug" occurs :
> dll is OK linked BUT at load time from java, no error appears (unsatisfied link 
> error should !! ), programm just stay silent and does not load the native.dll 
> library.
>  
>  
> File is :
> #include <stdio.h>
> #include <sys/ipc.h>
> #include <sys/shm.h>
> #include <sys/msg.h> 
> #include <sys/signal.h>
> #include <sys/types.h> 
> #include "HelloWorld_jni.h"
> JNIEXPORT void JNICALL
> Java_HelloWorld_sayHello( JNIEnv *env, jclass c )
> {
>     print("Hello World  !\r\n");
>     printf("Call  msgget()\r\n")
>     msgget(50  , 0660 | IPC_CREAT);
>     printf("msgget() has been called\r\n");
> }

because the ipc service must be available at runtime.
ipc-daemon2 in your case. this is cleary stated in the docs.

but better throw away cygipc (uninstall it) and use the new ipc library 
within cygwin1.dll and cygserver.
-- 
Reini Urban
http://xarch.tu-graz.ac.at/home/rurban/