error : unresolved external symbol "pid_ctrl" in function....

when i am trying to integrate c code into matlab to generate S function i am getting the following error (I am using microsoft visual studio as compiler)

>> legacy_code('compile',def)

### Start Compiling controltemp mex('-IC:\tempctrl', '-c', '-outdir', 'C:\Users\U335470\AppData\Local\Temp\tp48b6cbac_b35d_4df6_bd27_bd4b429fe862', 'C:\tempctrl\CtrTemp.c') Building with 'Microsoft Visual C++ 2015 (C)'. MEX completed successfully. mex('controltemp.c', '-IC:\tempctrl', 'C:\Users\U335470\AppData\Local\Temp\tp48b6cbac_b35d_4df6_bd27_bd4b429fe862\CtrTemp.obj') Building with 'Microsoft Visual C++ 2015 (C)'. Error using mex Creating library controltemp.lib and object controltemp.exp CtrTemp.obj : error LNK2019: unresolved external symbol PID_ctrl referenced in function PeriodicTemperatureControlPID

How to solve this ?

[Birdman]

Share your complete code please.

[VAMSI KRISHNA THANIKANTI]

I am sorry cvklpstunc, i cant share. this is a company's one. As per your known can you share which reason may cause this error.?