Question

VC++6.0 出现程序执行 link.exe 时出错.

Test.obj : error LNK2001: unresolved external symbol "int __cdecl MQTTAsync_connect(void *,struct MQTTAsync_connectOptions *)" (?MQTTAsync_connect@@YAHPAXPAUMQTTAsync_connectOptions@@@Z)
Test.obj : error LNK2001: unresolved external symbol "int __cdecl MQTTAsync_disconnect(void *,struct MQTTAsync_disconnectOptions *)" (?MQTTAsync_disconnect@@YAHPAXPAUMQTTAsync_disconnectOptions@@@Z)
Test.obj : error LNK2001: unresolved external symbol "int __cdecl MQTTAsync_sendMessage(void *,char *,struct MQTTAsync_message *,struct MQTTAsync_responseOptions *)" (?MQTTAsync_sendMessage@@YAHPAXPADPAUMQTTAsync_message@@PAUMQTTAsync_responseOption
s@@@Z)
Test.obj : error LNK2001: unresolved external symbol "void __cdecl MQTTAsync_destroy(void * *)" (?MQTTAsync_destroy@@YAXPAPAX@Z)
Test.obj : error LNK2001: unresolved external symbol "int __cdecl MQTTAsync_setCallbacks(void *,void *,void (__cdecl*)(void *,char *),int (__cdecl*)(void *,char *,int,struct MQTTAsync_message *),void (__cdecl*)(void *,int))" (?MQTTAsync_setCallbacks
@@YAHPAX0P6AX0PAD@ZP6AH01HPAUMQTTAsync_message@@@ZP6AX0H@Z@Z)
Test.obj : error LNK2001: unresolved external symbol "int __cdecl MQTTAsync_create(void * *,char *,char *,int,void *)" (?MQTTAsync_create@@YAHPAPAXPAD1HPAX@Z)
Debug/Test.exe : fatal error LNK1120: 6 unresolved externals

Answer 1

缺少MQTTAsync_connect
，MQTTAsync_disconnect 和MQTTAsync_destroy 的 定义。多半是没有加dll 之类的。

追问

MQTT这边样例程序只有提供3个头文件,

另外是.so文件，（这个好像用不了）

最后还有个未知的文件

这要怎么解决呀？

追答

.so 文件是给linux 用的。 VC++ 是无法用的。你从哪里下的MQTT？具体链接？