:sig
void file_append(String file_name, ...val)

:params
file_name : file name of file that should be written to
...val : one or more values that should be written into the file

:see
>sys

:content
Opens or creates a file and appends data to it.

The append transparently takes an exclusive file lock for the duration of the append operation. Concurrent writers are serialized, and `file_get_contents()` waits for in-progress writes to finish; callers do not manage locks manually.

:example
print("file_append example\n");