C++ dynamic libraries are usually stored as files with a .so suffix, and these files are also called shared objects. The .so file is a convention naming method used to represent dynamic link libraries on Linux and UNIX-like systems.
Dynamic libraries (.so files) have the following characteristics:
- Dynamic loading: The dynamic library is loaded into the memory when the program is running, and is dynamically linked with the program. Compared to static libraries, it does not require code to be copied into the final executable at compile time.
- Shared use: Multiple programs can share the same dynamic library file to reduce disk space consumption. If multiple programs depend on the same dynamic library, only one instance of the library needs to be kept in memory, thus saving memory space.
- Runtime dependencies: The program needs to ensure that the correct version of the dynamic library exists and is accessible at runtime. If the correct dynamic library cannot be found or the version does not match, the program may not run or an error may occur.
- Dynamic update: The update of the dynamic library is relatively easy. Dynamic libraries can be updated by replacing or upgrading .so files without recompiling the entire program.
- Symbol table: The dynamic library contains information about symbols such as functions and variables, so that other programs can refer to these symbols at compile time. The symbol table allows other programs to resolve these symbols and establish links with dynamic libraries at link time.
It should be noted that .so files are binary files in a specific format, and usually the compiler and linker toolchain will be responsible for generating and processing these files. When using a dynamic library, you need to ensure that the .so file is located in the correct path and can be accessed by the program.