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diff --git a/docs/tutorials/019/page02.html b/docs/tutorials/019/page02.html deleted file mode 100644 index 722797e6ba4..00000000000 --- a/docs/tutorials/019/page02.html +++ /dev/null @@ -1,154 +0,0 @@ -<HTML> -<HEAD> - <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> - <META NAME="Author" CONTENT="James CE Johnson"> - <TITLE>ACE Tutorial 019</TITLE> -</HEAD> -<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> - -<CENTER><B><FONT SIZE=+2>ACE Tutorial 019</FONT></B></CENTER> - -<CENTER><B><FONT SIZE=+2>Sharing your Memories</FONT></B></CENTER> - -<P> -<HR WIDTH="100%"> -We'll first take a look at the server side. As ususal with -co-operating applications, you need the server up and running first. -In the case of shared memory applications, the server will create the -shared memory segment. In this example, it will also remove the -segment when done. It is important to realize though that the segment -can be created external to your application and can persist beyond -it's lifetime. In fact, you can use shared memory to create a layer -of persistence between application instances (at least, until the -machine comes down.) -<HR> -<PRE> -<font color=red>// $Id$</font> - -<font color=red>/* - The client and server both need to know the shared memory key and - size. To prevent headaches, I've put those into a header they both - can share. - */</font> -<font color=blue>#include</font> "<font color=green>shmem.h</font>" - -<font color=blue>#if defined</font> (<font color=purple>ACE_LACKS_SYSV_SHMEM</font>) -int -main (int, char *[]) -{ - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>System V Shared Memory not available on this platform\n</font>"), - 100); -} -#else <font color=red>// ACE_LACKS_SYSV_SHMEM</font> -int -main (int, char *argv[]) -{ - <font color=red>/* - You can use the ACE_Malloc template to create memory pools - from various shared memory strategies. It's really cool. - We're not going to use it. - - Instead, I want to get to the roots of it all and directly - use ACE_Shared_Memory_SV. Like many ACE objects, this is a - wrapper around OS services. - - With this constructor we create a shared memory area to - use. The ACE_CREATE flag will cause it to be created if it - doesn't already exist. The SHM_KEY value (from shmem.h) - uniquely identifies the segment and allows other apps to - attach to the same segment. Execute 'ipcs -m' before and - after starting this app to see that the segment is created. - (I can't for the life of me correlate the SHM_KEY value back - to the key/id reported by ipcs though.) - */</font> - ACE_Shared_Memory_SV shm_server (SHM_KEY, SHMSZ, - <font color=#008888>ACE_Shared_Memory_SV::ACE_CREATE</font>); - - <font color=red>/* - The constructor created the segment for us but we still need - to map the segment into our address space. (Note that you - can pass a value to malloc() but it will be silently - igored.) The void* (cast to char*) that is returned will - point to the beginning of the shared segment. - */</font> - char *shm = (char *) shm_server.malloc (); - - <font color=red>/* - Since we're asking to create the segment, we will fail if it - already exists. We could fall back and simply attach to it - like the client but I'd rather not assume it was a previous - instance of this app that left the segment around. - */</font> - if (shm == 0) - ACE_ERROR_RETURN ((LM_ERROR, - "<font color=green>%p\n\t(%P|%t) Cannot create shared memory segment.\n</font>" - "<font color=green>\tUse 'ipcs' to see if it already exists\n</font>", - argv[0]), - 100); - - <font color=red>/* - This second pointer will be used to walk through the block - of memory... - */</font> - char *s = shm; - - <font color=red>/* - Out of curiosity, I added this output message. The tests - I've done so far show me the same address for client and - server. What does your OS tell you? - */</font> - ACE_DEBUG ((LM_INFO, - "<font color=green>(%P|%t) Shared Memory is at 0x%x\n</font>", - shm )); - - <font color=red>/* - At this point, our application can use the pointer just like - any other given to us by new or malloc. For our purposes, - we'll copy in the alpabet as a null-terminated string. - */</font> - for (char c = 'a'; c <= 'z'; c++) - *s++ = c; - - *s = '\0'; - - <font color=red>/* - Using a simple not-too-busy loop, we'll wait for the client - (or anyone else) to change the first byte in the shared area - to a '*' character. This is where you would rather use - semaphores or some similar "<font color=green>resource light</font>" approach. - */</font> - while (*shm != '*') - <font color=#008888>ACE_OS::sleep</font> (1); - - <font color=red>/* - Let's see what the client did to the segment... - */</font> - for (s = shm; *s != '\0'; s++) - putchar (*s); - - putchar ('\n'); - - <font color=red>/* - If you're done with the segment and ready for it to be - removed from the system, use the remove() method. Once the - program exits, do 'ipcs -m' again and you'll see that the - segment is gone. If you just want to terminate your use of - the segment but leave it around for other apps, use the - close() method instead. - - The free() method may be tempting but it doesn't actually do - anything. If your app is *really* done with the shared - memory then use either close() or remove(). - */</font> - if (shm_server.remove () < 0) - ACE_ERROR ((LM_ERROR, - "<font color=green>%p\n</font>", - "<font color=green>remove</font>")); - return 0; -} - -<font color=blue>#endif</font> <font color=red>/* ACE_LACKS_SYSV_SHMEM */</font> -</PRE> -<P><HR WIDTH="100%"> -<CENTER>[<A HREF="../online-tutorials.html">Tutorial Index</A>] [<A HREF="page03.html">Continue This Tutorial</A>]</CENTER> |