In PHP, stream_isatty() is useful when your application needs a specific operation rather than manually reproducing it. Checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode.
Stream functions work with PHP stream resources, wrappers, contexts or custom filters. Not every wrapper supports every operation.
What Is stream_isatty() in PHP?
Checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode.
Signature:
stream_isatty($stream): boolParameters:
$stream— An already opened stream resource, not a filesystem path string.
Return value: bool.
Example 1: Basic Usage
This first example shows the method or function in a minimal context. For environment-dependent operations, adapt the required path, stream or connection before running it.
<?php
if (defined("STDIN")) { var_dump(stream_isatty(STDIN)); }
The important operation is stream_isatty(). Checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode.
Example 2: Another Input or Scenario
The next example changes the input or surrounding context to show how the operation behaves in a second situation.
<?php
if (defined("STDOUT")) { var_dump(stream_isatty(STDOUT)); }
Compare the inputs and the handling of the return value with the first example. Avoid assuming that filesystem paths, resource states or binary bytes are interchangeable.
Practical Example: Applying the Operation
This example illustrates how the operation fits into a small application workflow. Paths, streams and secrets must be created or provided securely by the calling application.
<?php
if (PHP_SAPI === "cli" && defined("STDERR")) { var_dump(stream_isatty(STDERR)); }
Practical note: Checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode.
Important Behavior and Edge Cases
- Checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode.
- Check failure values and exceptions; do not assume every environment supports the same stream wrapper, extension or filesystem capability.
- When handling paths, streams or external input, validate inputs before using results and release resources after use.
Comparison With Related Functions
| Function or Method | Behavior |
|---|---|
stream_isatty() | checks attachment to a terminal device. |
stream_get_meta_data() | returns general stream metadata. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Assuming a successful check guarantees future operations | Treat the check as information at one moment; handle failures when the actual operation runs. |
| Assuming a resource result is always successful | Check false returns, actual byte counts, and resource state before using the result. |
| Confusing local and remote stream behavior | Read the wrapper capabilities and handle unsupported operations explicitly. |
Key Takeaways
stream_isatty()checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode.- Use appropriate input types and verify results before continuing.
- Prefer specialized, safer APIs when the operation concerns untrusted input, encryption or network traffic.
In summary: Checks whether a stream resource is connected to a terminal device, not simply whether PHP runs in CLI mode. Build in error handling and use this function where its specific behavior matches the application requirements.