EMULATOR issue can't find vs linker LINK.EXE

when i run the following command

aoc -march=emulator device/boardtest.cl

I get

Error: aoc: can't find visualstudio linker LINK.EXE.

Either use Visual Studio X64 Command Prompt or run %ALTERAOCLSDKROOT%\init_opencl.bat to setup your environment

but actually i had run the ini_opencl.bat to set the environment ,and at the cmd i can find link.exe

have anyone come across something similar to me ?