Search Order
When environment variables and command-line options are used together the compiler searches the directories in the following order:
- Command-line options '-I' and '-L',from left to right.
- Directories specified by environment variables,such as C_INCLUDE_PATH and LIBRARY_PATH.
- Default system directories.
Note:In day-to-day usage,directories are usually added to the search paths with the options '-I' and '-L'.
Creating a Library with ar
The GNU archiver ar combines a collection of objects files into a single archive file,also know as a library.An archive file is simply a convenient way of distributing a large number of related object files together.
- You can use the following command to create a static library:
$ ar cr libNAME.a file1.o file2.o ... filen.o
- The archiver ar also provides a "table of contents" option 't' to list the object files in an existing library.
$ ar t libNAME.a
EX：
main.c
mylib.h
func1.c
func2.c
使用
gcc -Wall * -c生成目标文件
目录
使用
ar cr创建一个自己的库文件：
libadd.a
第三种方法，使用默认库：
使用库文件编译程序，生成可执行文件：
add
注意文件的编译顺序：
第一种方法：
-L
第二种方法（通过环境变量）：
LIBRARY_PATH
注：添加：$LIBRARY_PATH是防止变量原有的的内容被冲掉，表示最佳环境变量
2020.11.18
