ipv6 address
I have little knowledge about ipv6 address. All I know is that it is longer than ipv4 address thus can be assigned to more hosts in the world. ipv6 addresses […]
dkim implementation details
The idea behind dkim is simple. You add a “DKIM-Signature:” in your email message. The stmp server receiving the email checks the header, pulls the dns record of the domain, […]
sha256 algorithm
sha256 is an algorithm to map a string of any length to a 256bit string(so called hash). The input of the algorithm is a string of any length but the […]
error: LNK2019: unresolved external symbol “void __cdecl fun1(void)” (?fun1@@YAXXZ) referenced in function _main
Today, I add two c files(one is fun.c, the other is its header file fun.h) to a c++ project, because I want to call a function(fun1) residing in the C […]
Build openssl with mingw to support Windows XP
Using pre-built openssl such as this one always causes trouble. They may require vc runtime dll like msvcr120.dll that is not available on deployed machine, or they are not compatible […]
How to check if an .exe/.dll is 32 bit or 64 bit?
Open the file with a text editor such as notepad++, the occurrence of “PE L” in the first several lines indicates it is 32 bit, while “PE d†” indicates 64 […]
qt imageformats folder
Many qt image related classes allow you to load an image from a file such as: QIcon ButtonIcon(“myprogrammingnotes.com.ico”); button->setIcon(ButtonIcon); Or, QPixmap pixmap(“myprogrammingnotes.com.ico”); QIcon ButtonIcon(pixmap); button->setIcon(ButtonIcon); That is very convenient. But […]
How to add app icon in Qt?
If you do not set an icon for your qt project, the built exe has a default icon, which seems a blank window. If you run the program, the icon […]
The FORMATETC structure of print screen clipboard
On windows, when you press the print-screen key, the screenshot is saved into system clipboard in 3 formats:CF_BITMAP, CF_DIB, and CF_DIBV5. The FORMATETC structure for these formats are: {2,1,-1,0,16}, {8,1,-1,0,5}, […]
build qt with ssl support
If you does not provide any parameter when configuring qt, the qt binaries you build sometimes support ssl, sometimes do not. If your build tool chain such as Mingw includes […]