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🔍 Understanding the $error Function in Uniface 10.4 ProcScript

⚠️ This blog post was created with AI assistance to help developers understand Uniface concepts better.

If you're working with Uniface applications, you've probably encountered errors during data input validation. The $error function is a powerful tool that helps you handle these situations gracefully. Let me break down what this function does and how you can use it effectively! 🚀

🤔 What is $error?

The $error function is a built-in ProcScript function that returns the Uniface message number for the current error. Think of it as your error detective - it tells you exactly what went wrong by giving you a specific error code number.

📋 Key Facts:

  • ✅ Returns a numeric error code
  • ⚠️ Can only be used inside error triggers
  • 🏗️ Works with all component types
  • 🎯 Helps identify specific field or entity data input errors

🛠️ How to Use $error

The beauty of $error lies in its simplicity. When a data input error occurs, you can check the specific error code and decide how to handle it. This means you can provide different responses for different types of errors!

💡 Real-World Example

Here's a practical example that shows how to handle an incorrect code error:


trigger error
variables
 vSelectedCode
endvariables

if ($error = 0126)  ; Error code 0126 = incorrect code
 message "Incorrect code. Select one from list."
 activate "CODES".exec(vSelectedCode) ; Show code selection form

 if ($status = 1)  ; User selected a valid code
  TYPECD = vSelectedCode  ; Apply the selected code
  return (0)  ; Continue processing
 else
  message "No code selected."
  return (-1)  ; Stop processing
 endif
else
 message $text("%%$error")  ; Show default error message
 return (-1)  ; Stop processing
endif

end; trigger
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🎯 Breaking Down the Example

Let's understand what happens in this code step by step:

  1. Error Detection 🔍: The code checks if the error number is 0126 (incorrect code error)
  2. User-Friendly Response 💬: Instead of showing a cryptic error, it displays a helpful message
  3. Interactive Solution 🖱️: It opens a form where users can select from valid codes
  4. Smart Recovery ✨: If the user picks a code, it automatically applies it and continues
  5. Fallback Handling 🛡️: For other errors, it shows the standard Uniface error message

🚀 Why This Approach is Powerful

This error handling pattern is excellent because:

  • User Experience 😊: Users get helpful guidance instead of confusing error codes
  • Productivity ⚡: Users can fix errors quickly without guessing
  • Flexibility 🔧: Different error codes can have different handling strategies
  • Professional Feel 💼: Your application feels polished and well-thought-out

🎪 Best Practices

When working with $error, keep these tips in mind:

  • 🎯 Be Specific: Handle common error codes with tailored solutions
  • 🔄 Provide Alternatives: Give users ways to fix the problem
  • 📝 Keep Messages Clear: Use simple, actionable language
  • 🛡️ Always Have a Fallback: Handle unexpected errors gracefully

🏁 Conclusion

The $error function might seem simple, but it's a cornerstone of good error handling in Uniface applications. By using it effectively, you can transform frustrating error situations into smooth, guided user experiences. 🌟

Remember: good error handling is not just about catching problems - it's about helping users solve them! 💪

Keywords: uniface, procscript, errorhandling, debugging

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