:sig
String signal_name(int sig)

:params
sig : POSIX signal number
return value : signal name such as `SIGSEGV`, or an empty string when unknown

:see
>runtime
capture_backtrace_string
backtrace_frames_string

:content
Returns a readable name for a POSIX signal number.

Example:

```uce
String name = signal_name(11);
// name == "SIGSEGV"
```

This is mostly useful in diagnostics and error reporting code.