The generation and use of static library files and dynamic library files under Linux __linux

Existing main.cpp, Function.cpp, Function.h
Both the static library file and the dynamic library file must be generated based on the. o file.
1. Static library file (LIBXXX.A):
The prefix must be lib and the suffix must be. A.
(1) Generate:
Ar-r Libmyfunction.a FUNCTION.O
A static library file will be generated for FUNCTION.O, and the filename must be libxxx.a.
A generated static library file can be extended. When you append a new. O to the end of a static library, you need to do this again: Runlib libxxx.a
(2) Use:
Need to perform before use: Runlib libxxx.a
The source program can use functions or classes contained in the static library Libmyfunction.a, simply link the static library file at compile time:
g++-O HelloWorld main.cpp-l.-L MyFunction
Where-L is a flag that uses a static or dynamic library, followed by. Indicates that the static library is in the current directory. If the static library is under/usr/lib, it can execute: g++-o helloworld main.cpp-l/usr/lib-l function. The function after-L does not require a LIB prefix and a. A suffix, which is automatically added when the command is executed.
2. Dynamic library file (libxxx.so)
(1) Generate:
You must add the-fpic option when compiling function.cpp into FUNCTION.O to indicate that it is not memory Related:
g++-fpic-c Function.cpp
And then to the FUNCTION.O Live dynamic library file:
g++-shared-o libmyfunction.so FUNCTION.O
Where the-shared option is the flag that generates the dynamic library file, the filename must be libxxx.so.
However, the generated libmyfunction.so is not available and needs to be added to the/usr/lib directory:
sudo mv Libmyfunction.so/usr/lib
However, this is still not available, and you need to update the record file/etc/ld.so.cache that records the available dynamic library files, using the command:
Ldconfig
Updates will be made automatically. The dynamic library can be used by functions that you write later.
(2) Use:
is similar to the use of static library files:
g++-O HelloWorld main.cpp-l.-L MyFunction