1, VxWorks的特点：

幻灯片 4

.O {font-size:149%;}

■

All functions exist in the same "space".

►

Name clashes may appear between different modules (libraries).

►

Use unique names (with prefix) for global functions!

●

Wrong:

config

,

test

,

read_bi

●

Right:

drvXy

Config

,

foo

Test

,

devAbc_

read_bi

►

Or make functions

static

.

■

vxWorks has no

main

function.

■

Every function (including the shell) can call any other function.

►

You don’t start

programs

from the shell, you call

functions

.

►

When name clash happens, you might call the wrong function.

幻灯片 5

.O {font-size:149%;}

■

Ending a thread does not clean up system resources.

2, VxWorks中不同模块下相同名字的全局变量仍占用同一块内存；

static可让变量仅在一个源文件中生效；

可能的内存问题：

幻灯片 6

.O {font-size:149%;}

■

Pro: Functions and threads can easily

…

►

exchange large amounts of data by reference (pointers).

►

access any hardware register (e.g. VME bus).

■

Con: Functions and threads can easily

…

►

overrun allocated memory or stack size (esp. with arrays)

►

overwrite system tables. (e.g. interrupt handler table at

NULL

)

►

overwrite program code.

►

modify global variables of other modules (e.g. drivers).

3, 入门指导：

幻灯片 9

.O {font-size:149%;}

► Important for beginners: VxWorks Programmer's Guide, Chapter 2

● All about tasks, semaphores, watchdog timers, interrupts

► Always helpful: vxWorks Reference Manual

● All vxWorks system functions

■ Run-time help: Type help on the vxWorks shell.

4，VxWorks shell使用注意：

1)最多只能传10个参数；

2)PPC结构中float和double无效；

3)可以直接使用shell创建全局变量；

5，写程序应注意以下错误处理：

■

Error checking is the key to a stable system.

►

Stability is limited by the weakest point!

■

Check arguments to API functions (esp. shell functions)

►

Never trust a user! Not even yourself.

■

Always check pointer arguments for validity.

►

Writing to

NULL

overwrites the interrupt handler table!

■

Check results of system functions (

malloc

,

fopen

,

…

)

►

System functions may fail and return

NULL

or

ERROR

.

►

Using these values unchecked may crash the system much later.

■

Check for "impossible" values (e.g. in

case

constructs

幻灯片 17

.O {font-size:149%;}