c++ - What is going on in this? -

-

i reading through someone's code, , calling functions this. "this" in block pointer virtual method table, , using offsets call function in said table. hack thing in case wondering.

    __asm {     mov edi,     lea ecx, [edi + 0x4]     mov edx, dword ptr ds:[ecx]     call [edx + 0x24] }

he has simpler bits of code call "this" + offset, confused on going on in one. can post vtable dump ida if @ all.

looks multiple inheritance. in such cases, there separate vtables each inherited class interface. so, 2nd , 3rd instructions calculate start of vtable specified inherited class interface. call obvious, 24 magic number, known offset function called in inherited class.


Comments

Post a Comment

Popular posts from this blog

android - getbluetoothservice() called with no bluetoothmanagercallback -

-
i getting getbluetoothservice() called no bluetoothmanagercallback error in android application. i have no idea causing or bluetooth manager callbacks. can give me idea of causing problem or start looking. by reading android source code, seems warning cannot about. source code shows if call bluetoothsocket#connect(); then call bluetoothadapter.getdefaultadapter().getbluetoothservice(null); the key here, null parameter passes in above line. due this, there no callback, , bluetoothsocket class throw out warning. since warning, not think need it. https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/bluetooth/bluetoothsocket.java line 306 https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/bluetooth/bluetoothadapter.java line 1610
Read more

sql - ASP.NET SqlDataSource, like on SelectCommand -

-
i'm working on asp.net. have sqldatasource query hardcoded on selectcommand: <asp:sqldatasource id="datasource1" runat="server" cancelselectonnullparameter="false" connectionstring="<%$ connectionstrings:s.properties.settings.connectionstring %>" selectcommand="select * [table] ([col1] case @col1_param when null col1 else @col1_param end) , ([col2] case @col2_param when null col2 else @col2_param end)" selectcommandtype="text"> <selectparameters> <asp:controlparameter controlid="textbox1" name="col1_param" propertyname="text" type="string" /> <asp:controlparameter controlid="textbox2" name="col2_param" propertyname="text" type="string" /> </selectparameters> what want if enter data on 1 textbox only, data display according textbox
Read more

ios - Undefined symbols for architecture armv7: "_OBJC_CLASS_$_SSZipArchive" -

-
i try using extractzipfile plugin @ this: https://github.com/phonegap/phonegap-plugins/tree/master/ios/extractzipfile but when compiler xcode 4.6.1 in sdk 6.1 throws error: undefined symbols architecture i386: "_objc_class_$_ssziparchive", referenced from: objc-class-ref in extractzipfileplugin.o ld: symbol(s) not found architecture i386 clang: error: linker command failed exit code 1 (use -v see invocation) i try issue @ here: undefined symbols architecture armv7 ssziparchive but shows error: /users/alienware/desktop/extractzipfile/ssziparchive/tests/ssziparchivetests.m:10:9: 'sentestingkit/sentestingkit.h' file not found i work phonegap , make app in ios, dump. update : try add ssziparchive.m compiler source , come new error: undefined symbols architecture i386: "_unzclose", referenced from: +[ssziparchive unzipfileatpath:todestination:overwrite:password:error:delegate:] in ssziparchive.o "_unzclosecurrentfil
Read more