wrong return

[bouji]

in my code sometimes the function returns wrong number or does not return.

[William Roeder]

bouji:  sometimes the function returns wrong number or does not return.

Do you really expect an answer? There are no mind readers here and our crystal balls are cracked, so we can't see your machine.
     How To Ask Questions The Smart Way. (2004)
          Be precise and informative about your problem

We can't see your broken code.

Always post all relevant code (using Code button) or attach the source file.

Use the debugger or print out your variables, including _LastError and prices and find out why. Do you really expect us to debug your code for you?
          Code debugging - Developing programs - MetaEditor Help
          Error Handling and Logging in MQL5 - MQL5 Articles (2015)
          Tracing, Debugging and Structural Analysis of Source Code - MQL5 Articles (2011)
          Introduction to MQL5: How to write simple Expert Advisor and Custom Indicator - MQL5 Articles (2010)