为什么出现“symbol referencing errors”？

_I2C_open                        C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_CSLDM642_LIB_                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_CACHE_enableCaching             C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_EMIFA_config                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
__CSL_init                       C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_config                      C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_MCASP_close                     C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_MCASP_config                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_MCASP_open                      C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_getConfig                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_start                       C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_xrdy                        C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_bb                          C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_sendStop                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_writeByte                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinRead                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinEnable                  C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinDirection               C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinWrite                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
>>   error: symbol referencing errors - './Debug/tone.out' not built


为什么会抱这样的警呀？
>>   error: symbol referencing errors - './Debug/tone.out' not built
其实“GPIO_pinDirection”这些函数在库里都已经声明过了。可为什么编译的时候就在函数名前加了个下划线，然后就抱错呢？

是CCS3.3的开发环境。

undefined                        first referenced
 symbol                              in file
---------                        ----------------
_I2C_outOfReset                  C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_open                       C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_open                        C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_CSLDM642_LIB_                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_CACHE_enableCaching             C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_EMIFA_config                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
__CSL_init                       C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_config                      C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_MCASP_close                     C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_MCASP_config                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_MCASP_open                      C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_getConfig                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_start                       C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_xrdy                        C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_bb                          C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_sendStop                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_I2C_writeByte                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinRead                    C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinEnable                  C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinDirection               C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
_GPIO_pinWrite                   C:\\CCStudio_v3.3\\boards\\evmdm642\\lib\\evmdm642bsl.lib
>>   error: symbol referencing errors - './Debug/tone.out' not built
报警信息贴漏了，全文是这样的

请确认下面的库已添加
C:\CCStudio_v3.3\C6000\csl\lib\cslDM642.lib