Refreshes the current Readline prompt and editing line in an interactive CLI program.
The objective is to understand the behavior and operational limits, not only the method name.
What It Does
Refreshes the current Readline prompt and editing line in an interactive CLI program.
Syntax and Return Value
readline_redisplay(...)The return value and exceptional cases depend on the call described here: Requires the readline extension and an interactive terminal; it does not print an application string.
Example 1: Basic Use
Run interactively with the readline extension; the redisplay call redraws the CLI prompt, not browser HTML.
<?php
$value = readline("Search: ");
readline_redisplay();
echo "Entered length: " . strlen($value);Example 2: A Second Scenario
Run interactively with the readline extension; the redisplay call redraws the CLI prompt, not browser HTML. This additional check distinguishes the method's result from connection or statement state.
<?php
$value = readline("Search: ");
readline_redisplay();
echo "Entered length: " . strlen($value);
echo "Line length: " . strlen((string) $value);Example 3: Practical Checks
Run interactively with the readline extension; the redisplay call redraws the CLI prompt, not browser HTML. This additional check distinguishes the method's result from connection or statement state.
<?php
$value = readline("Search: ");
readline_redisplay();
echo "Entered length: " . strlen($value);
echo "Readline redraw requested";Important Behavior and Edge Cases
Requires the readline extension and an interactive terminal; it does not print an application string.
For production use, also account for error handling, data validation, resource limits and environment-specific driver behavior.
Comparison with Related Approaches
| Approach | Important distinction |
|---|---|
| readline_redisplay | Refreshes the current Readline prompt and editing line in an interactive CLI program. |
| Related API / pattern | readline reads line input; readline_redisplay redraws an existing prompt. |
Common Beginner Mistakes
| Mistake | Correct approach |
|---|---|
| Assuming the happy path covers edge cases | Requires the readline extension and an interactive terminal; it does not print an application string. |
| Using a related API interchangeably | readline reads line input; readline_redisplay redraws an existing prompt. |
Key Takeaways
- Refreshes the current Readline prompt and editing line in an interactive CLI program.
- Requires the readline extension and an interactive terminal; it does not print an application string.
- readline reads line input; readline_redisplay redraws an existing prompt.
Choose this API or pattern when its exact semantics match your task, and verify the result against the database driver and runtime used by your application.