vfp dll .cannot find entry point解决办法

vfp dll ...cannot find entry point
Define   Class   mydll   as   Custom   olepublic
Function   htom
LPARAMETERS   time1  
minute1=INT(time1)*60+VAL(right(STR(time1,10,2),2))  
RETURN   minute1  
endfunc
enddefine


生成mydll.dll后

用test   =   createobject( "mydll.mydll ")
test.htom(3.30)
可以.

如果:
declare   integer   htom   in   "mydll.dll "   integer
htom(3.30)
则出现
cannot   find   entry   point   in   dll

自定义的DLL不能像系统API那样声明吗??

------解决方案--------------------
VFP的DLL不能用 声明