LPC2132學習中遇到的錯誤1

const int8 NoCheckBusy = 0;

const int8 CheckBusy = 1;

const int32 LCD_RS = 1<<4;

const int32 LCD_RW = 1<<5;

const int32 LCD_EN = 1<<6;

const int32 LCD_DATA = 0xff<<7;

在c文件lcd.c和main.c中都要用到，但是在編譯的時候出現(xiàn)如下的問題：

Error: L6200E: Symbol NoCheckBusy multiply defined (by main.o and lcd.o).

Error: L6200E: Symbol LCD_RS multiply defined (by main.o and lcd.o).

上網(wǎng)站arm.com/help/index.jsp?topic=/com.arm.doc.dui0435a/index.html" target="_blank">http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0435a/index.html上去查找，有如下結果：

L6200E:Symbol multiply defined (by and ).
There are two common examples where this occurs:
1)Symbol __semihosting_swi_guard multiply defined (by use_semi.o and use_no_semi.o).
This error is reported when functions that use semihosting SWIs are linked in from the C library, in the presence of the__use_no_semihosting_swiguard. See the ADS 1.2 Compilers and Libraries Guide, section 4.2.2, "Building an application for a nonsemihosted environment" and ADS 1.2 Developer Guide, Section 6.10.1, "Linker error __semihosting_swi_guard".
To resolve this, you must provide your own implementations of these C library functions.
The ADS 1.2 Examplesembedded directory contains examples of how to re-implement some of the more common SWI-using functions - see the fileretarget.c.
To identify which SWI-using functions are being linked-in from the C libraries:
1. Link with armlink -verbose -errors err.txt
2. Search err.txt for occurrences of __I_use_semihosting_swi
For example:
:
Loading member sys_exit.o from c_a__un.l.
reference : __I_use_semihosting_swi
definition: _sys_exit
:
This shows that the SWI-using function _sys_exit is being linked-in from the C library. To prevent this, you will need to provide your own implementation of this function.
2)Symbol __stdout multiply defined (by retarget.o and stdio.o).
This means that there are two conflicting definitions of__stdoutpresent – one inretarget.o, the other instdio.o. The one inretarget.ois your own definition. The one instdio.ois the default implementation, which was probably linked-in inadvertently.
stdio.ocontains a number symbol definitions and implementations of file functions likefopen,fclose,fflush, etc.stdio.ois being linked-in because it satisfies some unresolved references.
To identify why stdio.o is being linked-in, you must link with the linkers "verbose" switch, e.g.:
armlink [... your normal options...] -verbose -errors err.txt
Then studyerr.txt, so see exactly what the linker is linking-in, from where, and why.
To move forward, the user may have to either:
- Eliminate the calls likefopen,fclose,fflush, etc, or
- Re-implement the_sys_xxxxfamily of functions.
See the ADS 1.2 Compilers and Libraries Guide, section 4.10, "Tailoring the input/output functions".
具體是什么意思看的也不是很懂，后來看了別人的解決方法是：在頭文件中僅聲明變量，而把變量的定義都放到c文件中去，問題就解決了。
即把

const int8 NoCheckBusy = 0;

const int8 CheckBusy = 1;

const int32 LCD_RS = 1<<4;

const int32 LCD_RW = 1<<5;

const int32 LCD_EN = 1<<6;

const int32 LCD_DATA = 0xff<<7;

都放到lcd.c中就可避免該問題，時間不多，具體原因還有待研究。