Windows make you fool and to learn the computer, you'd better use the linux from now on !
-------By Dr. Sun
0. Install g++ and gdb on Ubuntu
sudo apt-get install g++
sudo apt-get install gdb
1. Compiling your main.c using gcc
gcc main.c -o test
2. From source code to an executable file, four steps are needed.
1) Preprocessing
gcc -E main.c -o main.i
2) Compilation
gcc -S main.i -o main.s
3) Assembly
gcc -c main.s main.o
4) Linking
gcc main.o -o test
3. Make your programs more portable.
gcc -Wall test.c
gcc -Werr test.c
4. Compile multiple source files
gcc -c -I ../include add.c -o add.ogcc -c -I ../include main.c -o main.o
gcc add.o main.o -o test
5. Compile a lib
1) Dynamic
gcc -shared -I ../include add.c -o libadd.so
2) Static
gcc -c -I ../include add.c
ar r libadd.a add.o
6. Use a lib
1) Dynamic
export LD_LIBRARY_PATH=/mnt/demo/srcgcc -c -I ../include main.c -o main.o
gcc -L . main.o -ladd -o test
2) Static
export LIBRARY_PATH=/mnt/fujie/demo/src
gcc -c -I ../include main.c -o main.o
gcc -L . main.o -static -ladd -o test
7. See the loading of the dynamic lib
ldd test
静态库链接时搜索路径顺序:
1. ld会去找GCC命令中的参数-L
2. 再找gcc的环境变量LIBRARY_PATH
3. 再找内定目录 /lib /usr/lib /usr/local/lib 这是当初compile gcc时写在程序内的
动态链接时、执行时搜索路径顺序:
1. 编译目标代码时指定的动态库搜索路径
2. 环境变量LD_LIBRARY_PATH指定的动态库搜索路径
3. 配置文件/etc/ld.so.conf中指定的动态库搜索路径
4. 默认的动态库搜索路径/lib
5. 默认的动态库搜索路径/usr/lib
有关环境变量:
LIBRARY_PATH环境变量:指定程序静态链接库文件搜索路径
LD_LIBRARY_PATH环境变量:指定程序动态链接库文件搜索路径