g++ - gcc warnings: defined but not used vs unused variable -


whenever compile code observe following 2 warnings:

warning: '<variable>' defined not used warning: unused variable '<variable>'

i tried google did not find helpful thread or blog difference between these 2 warnings.

example sample code snippet me or if duplicating existing thread please feel free refer.

i think difference kind of subtle here code snippet along compiler output demonstrates differences:

#include <iostream>  static const char * hello = "hello";  void foo() {     int i;      std::cout << "foo" << std::endl; } ... argenet@martell ~ % g++ /tmp/def_not_used.cpp -wall /tmp/def_not_used.cpp: in function ‘void foo()’: /tmp/def_not_used.cpp:6:9: warning: unused variable ‘i’ [-wunused-variable]      int i;          ^ /tmp/def_not_used.cpp: @ global scope: /tmp/def_not_used.cpp:3:21: warning: ‘hello’ defined not used [-wunused-variable]  static const char * hello = "hello";

so here local variable never used therefore compiler may omit while generating code , emits "unused variable" warning.

at same time, static c-style literal cannot emitted available wider scope (the whole .cpp file). however, not referenced code in module compiler warns "defined not used".


Comments

Post a Comment

Popular posts from this blog

android - Get AccessToken using signpost OAuth without opening a browser (Two legged Oauth) -

i using signpost oauth access data magento server. have read various tutorials on same , reach point open browser user can enter credentials. however, per requirement have automate part. hence, user should not browser page. have set-up done on server side ( magento ), hit url , returned call page. same through program in android. i have tried below, consumer = new commonshttpoauthconsumer(key, secret); provider = new commonshttpoauthprovider(oauth_init_url,access_token_url, authorize_url); try { provider.retrieverequesttoken(consumer, oauth.out_of_band); log.d("tokens" , consumer.gettoken() + " -- " + consumer.gettokensecret()); } and request tokens. dont know how bypass next step. tried directly accessing accesstoken (stupid of me) provider.retrieveaccesstoken(consumer, "mycallback://callback"); no luck, ends in oauth.signpost.exception.oauthnotauthorizedexception: authorization failed (server replied 401). ...
Read more

org.mockito.exceptions.misusing.InvalidUseOfMatchersException: mockito -

getting error org.mockito.exceptions.misusing.invaliduseofmatchersexception: invalid use of argument matchers! 1 matchers expected, 2 recorded. exception may occur if matchers combined raw values: //incorrect: somemethod(anyobject(), "raw string"); when using matchers, arguments have provided matchers. example: //correct: somemethod(anyobject(), eq("string matcher")); at when( getprogramservice .callservice(any(getprogramtype.class))) .thenreturn(jaxbresponse); please explain error , possible resolution the code posted looks fine; don't see problem it. code before or above causing exception. key here: invalid use of argument matchers! 1 matchers expected, 2 recorded. any , used above, doesn't return "special kind of null" or "special kind of getprogramtype"; don't exist. instead, returns null , side effect puts matcher on stack. whe...
Read more

google shop client API returns 400 bad request error while adding an item -

i'm working on solution add items in google shopping market java application. following tutorial real mess because of missing classes of laste release, after setting 1.5-beta maven managed make base example typecheck correctly classes. still can make simple task of adding 1 item. instead of posting whole code i'm posting part creates product feed. private product createproduct(string id) { product product = new product(); product.title = "red wool sweater"; product.content = new content( "text", "comfortable , soft, sweater keep warm on " + "cold winter nights. red , blue stripes."); product.appcontrol = new appcontrol(); product.appcontrol.addrequireddestination("productads"); product.externalid = id; product.lang = "it"; product.country = "it"; product.condition = "nuovo"; product.price = new price("eu...
Read more