# 4.38 FAQ-398 Why is there a compile error for the FFT function call in my program?

Last Update: 2/4/2015

Sometimes, you compile an Origin C function that calls the FFT function (for example, this one in our website) and see the following compile error:

Error, Function FFT@IAAAAAAAMAAABAAAMAAABAAA was called, but its body could not be located during linking.

This indicates that the body of the FFT function is not found. To solve the problem, please do the following two things:

1. Make sure that your program has included the file fft_utils.h, which is located in <Origin Program Folder>\OriginC\System.
2. Add the file <Origin Program Folder>\OriginC\Originlab\fft_utils.c to the current workspace.

Keywords:workspace, fourier transform