Returns a human-readable description of the last cURL transfer failure. This guide demonstrates its use in PHP code and explains when the result or side effect needs extra checks.
What It Does
Returns a human-readable description of the last cURL transfer failure.
Syntax and Parameters
The examples below show a real call to curl_error with suitable arguments. Read the function call in context: its connection, handle, input data or other prerequisites are created before use.
Requirements: cURL extension; HTTP client and transfer-handling tools.
Example 1: Core Behavior
The first case demonstrates the precise handle or result type.
<?php
$ch = curl_init('https://api.example.test/health');
curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 3, CURLOPT_CONNECTTIMEOUT => 2]);
curl_exec($ch);
echo "cURL transport error: " . (curl_error($ch) ?: "none");Observe the returned value or changed resource state. A successful function call can still require additional checks before a higher-level operation is considered successful.
Example 2: Alternative or Failure Case
The second case checks behavior under a different configuration or request.
<?php
$ch = curl_init('https://api.example.test/products');
curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 4, CURLOPT_CONNECTTIMEOUT => 2]);
curl_exec($ch);
echo "cURL transport error: " . (curl_error($ch) ?: "none");Compare the different inputs, environment assumptions or result checks. Do not use a transport-level success value as proof that all business-level requirements were met.
Practical Example: Applying the Rule
The practical case shows how to inspect the operation outcome instead of assuming success.
<?php
$ch = curl_init('https://api.example.test/orders');
curl_setopt_array($ch, [CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 5, CURLOPT_CONNECTTIMEOUT => 2]);
curl_exec($ch);
echo "cURL transport error: " . (curl_error($ch) ?: "none");In an application, convert low-level failures into controlled responses and log only non-sensitive diagnostic context.
Important Behavior and Edge Cases
Capture the message before resetting or reusing the handle; avoid exposing internal errors to visitors.
TLS validation, bounded timeouts and a destination allowlist are essential for network requests involving potentially untrusted targets.
Comparison with Related Functions or Patterns
| Approach | When it differs |
|---|---|
| curl_error | Returns a human-readable description of the last cURL transfer failure. |
| Related API or pattern | curl_errno returns the machine-readable numeric cURL error code. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Mistaking HTTP 404/500 status codes for libcurl transport failures | Capture the message before resetting or reusing the handle; avoid exposing internal errors to visitors. |
| Substituting a related API without checking its semantics | curl_errno returns the machine-readable numeric cURL error code. |
Key Takeaways
- Returns a human-readable description of the last cURL transfer failure.
- Capture the message before resetting or reusing the handle; avoid exposing internal errors to visitors.
- curl_errno returns the machine-readable numeric cURL error code.
Select this API or pattern based on its documented behavior and the trust boundaries in your own application, and test all external integrations against their actual deployments.