Delphi: function Result not emptied during for loop -

-

is normal?

for := 1 10     x.test;     x.test;    x.test;    x.test;  function test: string; begin   {$ifdef debug}  debugmessage('result check = '+result,3); {$endif}    result := result + 'a'; end;  10:39:59: result check =  10:39:59: result check = 10:39:59: result check = aa 10:39:59: result check = aaa 10:39:59: result check = aaaa 10:39:59: result check = aaaaa 10:39:59: result check = aaaaaa 10:39:59: result check = aaaaaaa 10:39:59: result check = aaaaaaaa 10:39:59: result check = aaaaaaaaa  10:39:59: result check =  10:39:59: result check =  10:39:59: result check =

function result stack not freed during loop? :o

result treated implicit var parameter function.

imagine if wrote out explicitly way:

procedure test(var result: string); begin   result := result + 'a'; end;  := 1 10   test(s);

then expect append s.

the fact throwing away result each time call why compiler decides finalise it. @gabr points out, elects not finalize implicit variable when inside loop optimisation.

if assign result of test string every time called test you'd see string longer each time, never re-initialized.

this why should initialize result variable. looks local variable, best thought of var parameter.


Comments

Post a Comment

Popular posts from this blog

Javascript line number mapping -

-
magically formatted comments change reported line number of javascript errors in browsers; this: //@line n "f" n line number , f file name. unfortunately, //@line appears ungoogleable. know there documentation on feature, , browsers support it? (i found references here , here .) from can find available in mozilla based browsers. it using js_setoptions command can turn these options on or off depending on values passed. https://developer.mozilla.org/en/js_setoptions
Read more

c# - Is it possible to remove an existing registration from Autofac container builder? -

-
something along lines: builder.registertype<mytype>().as<itype>(); builder.registertype<mytype2>().as<itype>(); builder.deregistertype<mytype>().as<itype>() var container = builder.build(); var types = container.resolve<ienumerable<itype>>(); assert.istrue(types.count == 1); assert.istrue(types[0].gettype == typeof(mytype2)); scenario: go through bunch of assemblies , go register types want make sure have 1 implementation of given type. need before create container. track on own nice if autofac me bit. this cannot done directly using containerbuilder , unless start on new one. mind you, having first built container should able construct new container filtering away unwanted types , reusing registrations first container. this: ... var container = builder.build(); builder = new containerbuilder(); var components = container.componentregistry.registrations .where(cr => cr.activator.limittype != typ...
Read more

php - Mysql PK and FK char(36) vs int(10) -

-
i have read mysql can handle indexes , searches better if tables keys integers rather char(36) uuid's. is worth converting int(10)? note: use 1 server , have have plans use multiple databases concurrently therefore removing 1 of big reasons using uuid. our tables innodb if makes difference. thanks in advance. usually rdbms can handle integer keys pk more efficient, other datatypes. reason how build index column, yes: long dont require string (or other typed) keys, should use integers. however: char(36) , int(10) far away being equal, because int(10) much smaller, char(36). dont know, if require many different keys, should keep in mind. update, complete last paragraph: int(10) 32-bit, char(36) 36 - ^byte^ (= 288-bit). not mean, int consumes less space, means, char(36) has 4 times more different keys.
Read more