[AGENT++] Single-threaded build under autoconf

[Ralph Siemsen]

Hi Frank,

I'm using single-threaded as a quick fix for locking problems
in code that I have inherited. I spent a week with valgrind
trying to fix the locks (in our code, not snmp++/agent++),
but ended up going in circles. Unfortunately I do not have
time to rewrite the whole thing.

Also, we are running this on a small embedded system with
a single CPU core. Here threads do not really help, in fact
the extra system calls for mutexes, and context switches,
actually reduce performance somewhat.

Any thoughts about agent++ single-threading? With the older
versions (before autotools) the _NO_THREAD option was picked
up from the snmp++ configuration. But with autotools that does
not seem to work anymore.

Cheers,
-Ralph

On Wed, Aug 27, 2014 at 10:54:09PM +0200, Frank Fock wrote:
> Hi Ralph,
> 
> First of all, many thanks for reporting those issues. They will be fixed
> with the next release. However, the IPX support will be dropped
> (also from the configuration) as I do not think that anybody is using
> that anymore. The MAC address support needs to be reorganized
> to be independent of the obsolete code, because there some users
> that need it.
> 
> Second, why do you need to compile a single threaded agent?
> 
> Best regards,
> Frank
> 
> 
> Am 27.08.2014 22:42, schrieb Ralph Siemsen:
> >I'm trying to build snmp++-3.3.4 without thread support.
> >
> >  ./configure --disable-threads
> >
> >This results in a syntax error in the generated config_snmp_pp.h.
> >
> >snmp++-3.3.4/include/snmp_pp/config_snmp_pp.h:79:5: error: #if with no expression
> >
> >79:  #if
> >80:  #define HAVE_PTHREAD 1
> >81:  #endif
> >
> >It looks like the root cause is in configure.ac, when threads are disabled,
> >then WITH_THREADS=0 is set, but WITH_PTHREAD variable remains undefined,
> >which causes the generated header file to be invalid.
> >
> >The following patch to configure.ac seems to fix it:
> >
> >--- snmp++-3.3.4/configure.ac   2014-01-24 08:30:38.000000000 -0500
> >+++ snmp++-3.3.4.new/configure.ac       2014-08-27 10:14:55.914449056 -0400
> >@@ -186,7 +186,7 @@
> >          ],
> >          [])
> >      ])
> >-], [WITH_THREADS=0]) # endif : --enable-threads
> >+], [WITH_THREADS=0;WITH_PTHREAD=0]) # endif : --enable-threads
> >  dnl Checks for libraries.
> >
> >You may of course prefer to format that a little more clearly, I just
> >packed it all on the same line to minimize the noise in the diff.
> >
> >~~~~~
> >
> >Also in the same configure.ac, the MacAddress / IpxAddress options look
> >suspiciously incorrect. Running configure --help shows:
> >
> >   --enable-macaddress     enable support of class MacAddress (default: off)
> >   --disable-macaddress    disable support of class MacAddress
> >   --enable-macaddress     enable support of class IpxAddress (default: off)
> >   --disable-macaddress    disable support of class IpxAddress
> >
> >The names of the options for IpxAddress seem to be duplicates? I do not use
> >these options, but noticed it while fixing the first problem.
> >
> >~~~~~
> >
> >Lastly, I am also trying to build single-threaded version of agent++-4.0.2.
> >There is no --disable-threads option in its configure script, but it does
> >check for pthread support on non-win32 systems. This causes the compile to
> >be done with gcc -pthread option, regardless of how snmp++ has been built.
> >
> >I was able to get it working by ripping out the pthread section from the
> >configure.ac script, but that clearly is not a good solution. Would you
> >have a suggestion on how best to handle this?
> >
> >Thanks,
> >-Ralph
> >
> >_______________________________________________
> >AGENTPP mailing list
> >AGENTPP at agentpp.org
> >https://oosnmp.net/mailman/listinfo/agentpp
> 
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