c++ - How to allocate from heap with the correct memory alignment for InterlockedIncrement function? -


this code seems work, have used interlockedincrement function correctly? correct memory alignment of m_count of primary concern. assume we're on x86-64 system , compile 64-bit application (in case matters). way, actual purposes can't declare m_count volatile long , use interlockedincrement(&m_count); must pointer data in heap.

#include <windows.h> #include <malloc.h>  class threadsafecounter { public:     threadsafecounter()     {         // arguments size , alignment correct?         void* placement = _aligned_malloc( sizeof(long), sizeof(long) );         m_count = new (placement) long(0);     }     ~threadsafecounter()     {         _aligned_free( const_cast<long*>(m_count) );     }      void addone()     {         interlockedincrement(m_count);     }      long getcount()     {         return *m_count;     }  private:     volatile long* m_count; };

the heap allocator aligns returned addresses native platform word size. 4 bytes x86, 8 bytes x64. using long, 32-bit on either platform msvc. no need jump through _aligned_malloc() hoop.


Comments

Post a Comment

Popular posts from this blog

asp.net - repeatedly call AddImageUrl(url) to assemble pdf document -

i'm using abcpdf , i'm curious if can recursively call addimageurl() function assemble pdf document compile multiple urls? something like: int pagecount = 0; int theid = thedoc.addimageurl("http://stackoverflow.com/search?q=abcpdf+footer+page+x+out+of+", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetochain(theid); } pagecount = thedoc.pagecount; console.writeline("1 document page count:" + pagecount); //flatten document (int = 1; <= pagecount; i++) { thedoc.pagenumber = i; thedoc.flatten(); } //now try again theid = thedoc.addimageurl("http://stackoverflow.com/questions/1980890/pdf-report-generation", true, 0, true); //assemble document while (thedoc.chainable(theid)) { thedoc.page = thedoc.addpage(); theid = thedoc.addimagetoc...
Read more

java - Android recognize cell phone with keyboard or not? -

in android app, want detect user's device if device has keyboard(like motorola milestone) , show corresponding user interface. guys know how that? ! regards justicepenny http://developer.android.com/reference/android/content/res/configuration.html public int keyboard the kind of keyboard attached device. 1 of: keyboard_nokeys, keyboard_qwerty, keyboard_12key. that's it!
Read more

iphone - How would you achieve a LED Scrolling effect? -

how achieve led scrolling effect example below? led sign - led ticker emulator iphone , ipad http://img.skitch.com/20101201-rsfh4p1bajb1wp94k466pdpiuj.preview.jpg sometimes remunerates comment in other posts :) have put code you, should implement font '8pin matrix' realistic feeling. uilabel *label; - (void)viewdidload { [super viewdidload]; label = [[uilabel alloc]initwithframe:cgrectmake(10, 50, 300, 20)]; label.font = [uifont fontwithname:@"courier-bold" size:16.0]; label.backgroundcolor = [uicolor blackcolor]; label.textcolor = [uicolor greencolor]; label.linebreakmode = uilinebreakmodecharacterwrap; // otherwise "…" label.text = @"this led text scrolled "; // blanks space between [self.view addsubview:label]; [nstimer scheduledtimerwithtimeinterval:0.12f target:self selector:@selector(scrolllabel) use...
Read more