程序说明

解析命令行输入的命令并执行。

命令格式

i2c read <0x45>
i2c write <0x45> <0x33>

编译执行

user@ubuntu:~/work/c-study/Parse-string-command$ gcc -o app main.c && ./app "i2c read 0x45"
execute i2c read command
reg    = 0x45(h), 69(d)

user@ubuntu:~/work/c-study/Parse-string-command$ gcc -o app main.c && ./app "i2c write 0x45 0x33"
execute i2c write command
reg    = 0x45(h), 69(d)
data   = 0x33(h), 51(d)

# 使用 gcc -D 在编译时刻定义调试宏
user@ubuntu:~/work/c-study/Parse-string-command$ gcc -o app main.c -DDEBUG && ./app "i2c write 0x45 0x33"
sizeof(argv[1]) = 19
argv[1] = i2c write 0x45 0x33
command = i2c write 0x45 0x33
cmd[0] = i2c
cmd[1] = write
cmd[2] = 0x45
cmd[3] = 0x33
execute i2c write command
reg    = 0x45(h), 69(d)
data   = 0x33(h), 51(d)

修订记录

1. 修正参数异常导致的段错误

修正前效果:

user@ubuntu:~/work/c-study/Parse-string-command$ gcc -o app main.c -DDEBUG && ./app "i2c write 0x45"
sizeof(argv[1]) = 14
argv[1] = i2c write 0x45
command = i2c write 0x45
cmd[0] = i2c
cmd[1] = write
cmd[2] = 0x45
段错误 (核心已转储)

修正后效果:

user@ubuntu:~/work/c-study/Parse-string-command$ gcc -o app main.c -DDEBUG && ./app "i2c write 0x45"
sizeof(argv[1]) = 14
argv[1] = i2c write 0x45
command = i2c write 0x45
cmd[0] = i2c
cmd[1] = write
cmd[2] = 0x45
err: ptr == NULL, line = 78