c - What aspects of signed left shift are undefined with GCC? -

-

basically asking translation of:

gcc not use latitude given in c99 treat aspects of signed `<<' undefined, subject change.

(gcc 4.8.1 manual, paragraph 4.5)

what 'latitude' given? aspects?

other answers have pointed out aspects of << undefined behavior. guess want "translation" of gcc common language.

if behavior undefined c standard, compiler implementors can take "latitude" suits them if such case occurs. in particular, don't have implement diagnostic or detection of case, , may pretend never happens. responsability of programmer write program such behavior defined.

in case of left shift, means compiler not have check overflow , can pretend loop like

for (int = 1; > 0; <<= a) {  .... change in complicated way ... }

would never terminate.

the sentence citing indicates don't such thing, yet, future versions of gcc might so.


Comments

Post a Comment

Popular posts from this blog

java - Run a .jar on Heroku -

-
i trying run .jar file on heroku, , can't find instructions anywhere on how this. have read wants me compile uploading heroku. possible, , if is, how this? if helps, trying run minecraft craftbukkit server, , don't have pom.xml file yet. you didn't provide details i'll try give , people reaches question way it. first of all, create heroku account , create heroku application (assumed have done that). second, need generate application jar , upload heroku. so, open terminal , install heroku cli (assuming unix terminal): $ sudo npm install -g heroku-cli you need have npm , nodejs installed, can check link: https://www.digitalocean.com/community/tutorials/how-to-install-node-js-on-ubuntu-16-04 once done that, can use npm update node version acceptable heroku-cli: $ sudo npm install -g n $ sudo n 7.10.0 and run: $ sudo npm install -g heroku-cli in order deploy jars, need install deploy plugin: $ sudo heroku plugins:install heroku-cli-deploy ...
Read more

java - Jtable duplicate Rows -

-
Image
when add new rows in jtable duplicate rows many times this method update jtable public final void tableaucomande(){ ((defaulttablemodel)tabcommande.getmodel()).getdatavector().clear(); session s=hibernateutil.getsessionfactory().opensession(); criteria cr1= s.createcriteria(commande.class); list <commande> lcs=cr1.list() ; criteria cr2= s.createcriteria(lignecommande.class); list <lignecommande> lck=cr2.list() ; if(lcs.size()!=0 && lck.size()!=0) { (commande lc:lcs) { for(lignecommande lig:lck){ ((defaulttablemodel)tabcommande.getmodel()).addrow(new object[]{ lc.getid_cmd(),lc.getnumcmd(),lc.getdate_cmd(),lc.getclient().getnomprenom(), lig.getproduit().getlib_prd(),lig.getquantite(),lig.getproduit().getid_prd() }); } } // tabcommande.setrowselectioninterval(tabcommande.getrowcount()-1,tabcommande.getrowcount()-1); } } this code add add data rows displaye...
Read more

validation - How to pass paramaters like unix into windows batch file -

-
i need pass various parameters .cmd file unix format file.cmd -configuration=value -source=value -flag but, try this: startlocal @echo off cls setlocal set cmdline=%* set configuration= set source= set badargs= set validation= goto main :splitargs echo splitargs(%*) if "%*" neq "" ( /f "tokens=1,2,* delims== " %%i in ("%*") call :assignkeyvalue %%i %%j & call :splitargs %%k ) goto :eof :assignkeyvalue echo assignkeyvalue(%1, %2) if /i %1==-configuration ( set configuration=%2 ) else if /i %1==-source ( set source=%2 ) else ( rem append unrecognised [key,value] badargs echo unknown key %1 set badargs=%badargs%[%1, %2] ) goto :eof :validate echo validating set validation=fail if defined configuration ( echo -configuration ok if defined source ( echo -source ok if not defined badargs ( set validation=success ) ) ) goto :eof :main cl...
Read more