This methodology, also known as "shared components" or "archive libraries", groups together multiple compiled object code files into a single file known as a library. Typically C functions/C++ classes and methods which can be shared by more than one application are broken out of the application's source code, compiled and bundled into a library. The C standard libraries and C++ STL are examples of shared components which can be linked with your code. The benefit is that each and every object file need not be stated when linking because the developer can reference the individual library. This simplifies the multiple use and sharing of software components between applications. It also allows application vendors a way to simply release an API to interface with an application. Components which are large can be created for dynamic use, thus the library remain separate from the executable reducing it's size and thus disk space used. The library components are then called by various applications for use when needed.

There are two Linux C/C++ library types which can be created:

1. Static libraries (.a): Library of object code which is linked with, and becomes part of the application.
2. Dynamically linked shared object libraries (.so): There is only one form of this library but it can be used in two ways.
   1. Dynamically linked at run time but statically aware. The libraries must be available during compile/link phase. The shared objects are not included into the executable component but are tied to the execution.
   2. Dynamically loaded/unloaded and linked during execution (i.e. browser plug-in) using the dynamic linking loader system functions.

Library naming conventions:

Libraries are typically names with the prefix "lib". This is true for all the C standard libraries. When linking, the command line reference to the library will not contain the library prefix or suffix.

http://blog.udn.com/keithmin/631169

前言

動態連結程式庫(Shared library)是在程式開始執行時才載入的，其優點在於(1)減少執行檔的大小，(2)更新程式庫而無需重新編譯其他程式，以及(3)甚至可在程式執行時更改程式庫。

http://xifage.com/gcc-4-6-warning-variable-set-but-not-used/

关于dynamic library存在却找不到的解决方法

有朋友问在linux中动态链接库.so文件在机器上却无法load，以mplayer为例，编译时正常。但运行时却出现如下问题：

./mplayer

 原文網址 http://hi.baidu.com/lanyi_522/blog/item/c944663412e248bcd0a2d309.html

http://www.jb.man.ac.uk/~slowe/cpp/itoa.html

如上網址 最後的

#!/bin/bash

Date=$(date +'%Y%m%d-%H%M')

http://fanqiang.chinaunix.net/a4/b8/20010704/130401784_b.html

obj-m:=spi_module.o

KERNEL_PATH=/home/......../2.6.29

http://hi.baidu.com/grdd/blog/item/9b4e9b8f99ca82f6513d92e4.html

get_opt()函數：

select（I/O多工機制）

http://yuanma.org/data/2007/0201/article_2213.htm

在基于ARM的嵌入式系統開發中，常常用到交叉編譯的GCC工具鏈有兩種：

嵌入式作業系統橫向解析