why the output of "ceil" becomes non-integer in embedded matlab function?

I am working with embedded Matlab function in simulink and using the function "ceil" inside the embedded block. When I plot the output or observe the variable containing the function "ceil" in command window, it looks okay; always integer. But, if I try to use that variable containing "ceil" in other variables, it returns an error indicating the output of "ceil" function is non-integer. So, How can I solve this problem? Please help me. Thanks.

[Michael Haderlein]

Could you please post the line which throws the error?