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
靜態庫鏈接時搜索路徑順序:
1. ld會去找GCC命令中的參數-L
2. 再找gcc的環境變量LIBRARY_PATH
3. 再找內定目錄 /lib /usr/lib /usr/local/lib 這是當初compile gcc時寫在程序內的
動態鏈接時、執行時搜索路徑順序:
1. 編譯目標代碼時指定的動態庫搜索路徑
2. 環境變量LD_LIBRARY_PATH指定的動態庫搜索路徑
3. 配置文件/etc/ld.so.conf中指定的動態庫搜索路徑
4. 默認的動態庫搜索路徑/lib
5. 默認的動態庫搜索路徑/usr/lib
有關環境變量:
LIBRARY_PATH環境變量:指定程序靜態鏈接庫文件搜索路徑
LD_LIBRARY_PATH環境變量:指定程序動態鏈接庫文件搜索路徑