pyqt - Conflict between two linux shared objects defining the same function name -


my problem deals python, qt, pyqt , other stuff, question how linux's ld.so works.

the question

if program loads 2 different shared libraries both have same entry point name (i.e. both define function same name , signature) how can tell version calling?

my problem

i have third party, proprietary linux application written in c++ (though original language irrelevant) , it's linked dynamically qt3.3. application embeds python interpreter can used write scripts it.

you can use application's embedded python instead of original 1 using command such as:

/path/to/the/program/python

and shows following:

python 2.7.1 (r271:86832, sep 16 2011, 18:16:32)  [gcc 4.1.2 20080704 (red hat 4.1.2-46)] on linux2 type "help", "copyright", "credits" or "license" more information. >>>

using gcc 4.1.2 have built , installed pyqt4 sources, against qt4 libraries system has. believe build successful because can run small pyqt4 application using:

/path/to/the/program/python mypyqtapp.py

however, if load program gui , load same script, crashes @ first pyqt4 call, instantiation of qapplication class.

since python environment same, suspect might kind of shared library conflict between qt3 , qt4. however, command strace -e trace=file reveals python locating , loading right qt4 libraries in both cases.

so, question if program loads 2 shared different libraries define same function, how know it's calling right one? linux loader ld.so somehow qualify entry points file name or something? suspect problem might lie there, app has loaded 2 different instances of qapplication , it's calling wrong one, how ld.so works internally escapes me.

it might problem caused different.

thank you.

conflict symbol detected on linkage(ld) stage, loader(ld-linux.so) don't check conflict symbol.

when multiple library providing duplicated symbol, 1 first loaded used.

actually can make use of feature. providing ld_preload=overwrite.so, overwrite.so can overwrite function program needed.


Comments

Post a Comment

Popular posts from this blog

curl - PHP fsockopen help required -

i trying work on cloudflare api , have found in documentation. unfortunately have no idea how can use in fsockopen or through curl. here example of post request. need know how can make request below data post using curl or fsockopen curl https://www.cloudflare.com/api_json.html -d 'a=cache_lvl' \ -d 'tkn=8afbe6dea02407989af4dd4c97bb6e25' \ -d 'email=sample@example.com' \ -d 'z=example.com' \ -d 'v=agg' here link cloudflare https://www.cloudflare.com/docs/client-api.html#s4.2 try one: $ch = curl_init("https://www.cloudflare.com/api_json.html"); curl_setopt($ch, curlopt_returntransfer,1); curl_setopt($ch, curlopt_followlocation, 1); curl_setopt($ch, curlopt_ssl_verifypeer,false); // handling of -d curl parameter here. $param = array( 'a' => 'cache_lvl', 'tkn' => '8afbe6dea02407989af4dd4c97bb6e25', 'email' => 'sample@example.com', 'z' =...
Read more

HTTP/1.0 407 Proxy Authentication Required PHP -

i working in restricted network/limited access internet. since have use proxy make web service call. here php code calling web service , response . $client = new soapclient("http: //www.xyz.com/abc/wsdls/login.wsdl", array("trace" => 1, "exceptions" => 1, 'proxy_host' => $proxy_host, 'proxy_port' => $proxy_port, 'proxy_login' => $proxy_login, 'proxy_password' => $proxy_password)); response is fatal error: uncaught soapfault exception: [wsdl] soap-error: parsing wsdl: couldn't load ' http://www.xyz.com/abc/wsdls/login.wsdl ' : failed load external entity if copy url error message , paste in browser(with same proxy settings) works. 2nd scenario is, if pass values instead of variables giving me diffarant response $client = new soapclient("http: //www.xyz.com/abc/wsdls/login.wsdl", array("trace" => 1, "exceptions" => 1, 'proxy_host' ...
Read more

c# - Resource not found error -

i have problem accessing method on homecontroller. show code of method : [httpget] public actionresult decriptidentifiantetredirige(string login_crypter, string mdp_crypter) { string loginacrypter = _globalmanager.protegemotdepasse(login_crypter); string mdpacrypter = _globalmanager.protegemotdepasse(mdp_crypter); user userapp = new models.user(login_crypter, mdp_crypter); if (userapp.authentificationvalidee(userapp.userlogin, userapp.password)) { session["name"] = userapp.userlogin; return redirecttoaction("accueil", "home"); } else { return redirecttoaction("validerauthentification", "home"); } } then in routeconfig.cs wrote route : routes.maproute( name: "authentificationapresdecryptage", url: "{controller}/{action}/{login_crypter}/{mdp_crypter}", defaults: new...
Read more