A typical error in bash programming
$a=df|grep vda1|awk ‘{print $5}’ Above is a typical error in Bash programming for bash newbies, especially for savvy programmers familiar with other languages but bash. There are two errors in […]
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input submit tag
<input type=”submit” name=”submit” value=”submit”> There are so many submit in the input tag, what do they mean? We often use <input> in a form to transfer back some user input […]
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 […]