warn()
Compatibility
Supported languages: Lua 5.4, Luau, JavaScript and HTML/inline JavaScript; other languages use rustic.print/rustic.warn.
Use a compatible native engine build and the language tools required by your binding. This does not establish browser/mobile export or release qualification for every OS.
The signature below is the shared reference notation; language examples show the actual binding syntax. Question marks mark optional arguments and explicit defaults are shown where recorded. Do not copy reference notation as a typed declaration.
See Feature status and compatibility for API 1.0/1.1 and per-method restrictions. Engine release tags and Docs v0.1 are independent versions.
Signature
warn(...)
Setup and usage
Log lifecycle transitions and recoverable errors. Avoid per-frame logging outside short debugging sessions because bounded queues can drop excessive output.
Parameters
| Variable | Type | Required | Description |
|---|---|---|---|
level | string | Yes | debug, info, warn, or error. |
message | string | Yes | Human-readable diagnostic text. |
Return and timing
No value. The message is queued for the bounded console sink.
Execution behavior
Core write timing differs between immediate Lua host calls, deferred JavaScript/Web commands and external SDK query flushes. Scheduled actions advance with the scene clock; synchronous queries evaluate at the call. Follow execution rules and the return/timing notes for this category.
Language examples
Use these snippets inside Start/on_start after generating the Programming Workspace and attaching the script. Python imports rustic, Game and instance from rustic; C++ includes rustic.hpp; C includes rustic.h; C# uses using static Rustic; Java runs inside a Rustic subclass; PHP declares global $rustic, $Game, $instance in its callback. HTML uses an inline script in a ui/ asset. See Lifecycle callbacks for complete registration examples. Public-property examples require a declared integer health property. Scene examples require the named objects to exist before Play.
Lua 5.4
rustic.log('info', 'player spawned')
print("spawned")
warn("low health")JavaScript
rustic.log('info', 'player spawned');
print("spawned");
warn("low health");Python
rustic.log('info', 'player spawned')
rustic.print("spawned")
rustic.warn("low health")C++
rustic.log("info", "player spawned");
rustic.print("spawned");
rustic.warn("low health");C#
rustic.log("info", "player spawned");
rustic.print("spawned");
rustic.warn("low health");Luau
rustic.log('info', 'player spawned')
print("spawned")
warn("low health")C
rustic.log("info", "player spawned");
rustic.print("spawned");
rustic.warn("low health");Java
rustic.log("info", "player spawned");
rustic.print("spawned");
rustic.warn("low health");PHP
$rustic->log('info', 'player spawned');
$rustic->print("spawned");
$rustic->warn("low health");HTML / inline JS
rustic.log('info', 'player spawned');
print("spawned");
warn("low health");Shared Logging constraints
- In Lua and JavaScript, print(...) writes an info entry and warn(...) writes a warning entry to the Rustic Console. Lua separates multiple arguments with tabs; JavaScript separates them with spaces. Use rustic.log for an explicit level. External programs must not print diagnostics to stdout; stdout is reserved for protocol responses.
- Every gameplay language calls the engine-owned API. Rustic supplies SDKs and dispatches callbacks; scripts do not parse requests or serialize responses. See the language guide for complete setup and callback registration.
Errors and debugging
Read the constraints above and the Console diagnostic. Invalid types, non-finite values, stale targets or unavailable native services can fail validation. A failed callback disables the behavior; a failed source reload keeps the last good instance. Exact error messages depend on the language adapter. See Troubleshooting.