[QT] add knowledge supplement of third-party database

Write it at the front

This article will focus on QT The process and principle of adding a third-party library is a knowledge supplement , Including static library and dynamic library 、MinGW and MSVC、make and makeinstall、debug and release、 Environmental variables, etc .（C++ In the same way ）

1、 library

1.1、 Static library

Windows ：.lib
Linux\Mac：.a
The static library will be directly copied into the target program when compiling .
（ After the program is packaged , Put it on a computer without an environment , It can also operate normally ）

2.2、 Dynamic library

Windows ：.dll
Linux：.so
Mac: dylib
Dynamic libraries are not copied to the target program at compile time , Will only be called at runtime .
（ After the program is packaged , Put it on a computer without an environment , May not function properly ; The corresponding dll Dynamic libraries are packaged together for normal operation ）

2、 compiler

2.1、MSVC

MSVC Microsoft 's VC compiler , It is mainly used for windows Lower development .
( Use msvc When importing a third-party library , Library files are usually .lib)

2.2 MinGW

MinGW Means Minimalist GNU on Windows Abbreviation . It's a freely available and freely distributed Windows Specific header files and usage GNU Toolset import collection , Allow you to stay GNU/Linux and Windows Platform generates local Windows Programs without the need for third-party runtime libraries .
( Use mingw When importing a third-party library , Library files are usually .a)

MinGW And MSVC The difference between

3、make and make install

3.1、make

make It's for compiling , It is from Makefile Read instructions in , Then compile .
If you use static libraries , It only needs make that will do , Generate .lib perhaps .a.

3.2、make insatll

make install It's for installation , It also comes from Makefile Read instructions in , Install to specified location .
If you use dynamic libraries , need make insatll, Generate .dll perhaps .so. In general, you need to configure environment variables before importing a dynamic library .

4、 Configure environment variables

Configuration environment variables are generally executable files .exe The catalog of .
If you configure a third-party library 、 Is the directory for configuring the dynamic library , Generally in make insatll Later generated bin Directory , It contains dll or .exe file

5、 stay windows Call the static library

（ Static libraries only need to be compiled , no need make insatll）

Usually use first cmake Generate makefile, perhaps sln

5.1 MingGw

use mingw32-make compile
Get the compiled .a file
Configure... In code .a Files and header files (include)

5.2 MSVC

open camke Generated sln（ use vs2019）
choice Debug perhaps Release,x86\x64
choice ALL_BUILD, Right click , To regenerate the
Get output .lib file , distinguish debug and release
Configure... In code .lib Files and header files (include)

6、 stay windows Call dynamic library

（ Dynamic library needs make insatll）

Usually use first cmake Generate makefile, perhaps sln

5.1 MingGw

use mingw32-make compile
And then again mingw32-make install
In the output directory, there is usually a bin Catalog , There are dll or exe
Put this bin Add the path of the directory to the environment variable
Get the compiled .a file ( Generally in lib Under the table of contents )
Configure... In code .a Files and header files (include)

5.2 MSVC

To be added …

7、 stay VS2019 Add a third-party library

Visual Studio Configure the third party C/C++ Method of library

Generally, dynamic libraries are configured like this


The static library is configured like this