c - Why printf("test"); does not give any error? -

-

if int x=printf("test"); executes safely, without error in because printf returns int value (the length of data has printed.) if not storing integer value:

printf("text");

why don't error this?

many functions in c return something. whether programmer decides value them - , ignoring return code leads bugs... in case of printf(), return value seldom useful. provided allow following code:

int width;  width = printf("%d", value); // find out how wide while (width++<15) printf(" "); width = printf("%s", name); while (width++<30) printf(" ");

i'm not saying that's code (there other ways too!), describes why function return value isn't used often.

if programmer decide ignore return value, there isn't compiler error - value merely forgotten. it's bit buying something, getting receipt, , dropping on floor - ignore returned value.

the latest compilers can instructed flag code returned values ignored. these compilers can taught functions' returns significant , aren't. printf() in second category.


Comments

Post a Comment

Popular posts from this blog

wordpress - (T_ENDFOREACH) php error -

-
creating wordpress website , i'm getting following php error: parse error: syntax error, unexpected 'endforeach' (t_endforeach) in /home/soralmedia/public_html/wp-content/themes/soral media/woocommerce/myaccount/my-orders.php on line 98 here's code file: <?php /** * orders * * shows recent orders on account page. * * template can overridden copying yourtheme/woocommerce/myaccount/my-orders.php. * * however, on occasion woocommerce need update template files , (the theme developer). * need copy new files theme maintain compatibility. try this. * little possible, happen. when occurs version of template file will. * bumped , readme list important changes. * * @see http://docs.woothemes.com/document/template-structure/ * @author woothemes * @package woocommerce/templates * @version 2.5.0 */ if ( ! defined( 'abspath' ) ) { exit; } $my_orders_columns = apply_filters( 'woocommerce_my_account_my_orders_columns', array( ...
Read more

Export Excel workseet into txt file using vba - (text and numbers with formulas) -

-
i new vba have developed code use in excel move text/numbers txt file. issue have 3 functions need go same txt file. when run first function has set fs = createobject("scripting.filesystemobject") set = fs.createtextfile(module1.nys45uploadfilename, true) a.writeline (str) a.close. the other 2 functions had save. set fs = createobject("scripting.filesystemobject") set = fs.savetextfile(module1.nys45uploadfilename, true) a.writeline (str) a.close. the first function go txt file, other 2 error object doesn't support property or method. when changed 3 create last function goes txt file. can not figure out word use in order make other 2 functions follow txt file in order keyed. the entire code follows private sub addrecord_click() on error goto errhandler module1.nys45uploadfilename = application.getsaveasfilename(filefilter:="textfiles (*.txt), *.txt") if module1.nys45uploadfilename = "false" exit sub ...
Read more

java - Sql2o with postgres, No results were returned by the query -

-
the other questions i've found title deal non-select queries. i'm using java 8, sql2o 1.5.4, , postgresql 9.5.3. my userservice looks like: public class userservice { private final pgservice pgservice; public userservice(pgservice _pgs) { this.pgservice = _pgs; } public user getuserbyid(int id) { string sql = "select id, firstname, lastname, email, team_id teamid users id = :id;--"; user user; try (connection c = pgservice.getconnection()) { user = c.createquery(sql) .addparameter("id", id) .executeandfetchfirst(user.class); } return user; } } my user looks like: public class user { private int id; private string firstname; private string lastname; private string email; private string passhash; private int teamid; /*getters , setters*/ } my test looks like: public class userservicetest { pr...
Read more