:sig
s64 file_seek(u64 h, s64 offset, s64 whence)

:params
h : handle from file_open()
offset : byte offset relative to whence
whence : 0 from start, 1 from current, 2 from end
return value : the new absolute offset, or -1 on error

:content
Moves a handle's read/write offset for random access. Combine with `file_read()` / `file_write()` to jump around a file; `file_tell()` reports the current offset.

:example
u64 w = file_open("/tmp/doc-seek.txt", "w");
file_write(w, "hello world");
file_close(w);
u64 r = file_open("/tmp/doc-seek.txt", "r");
file_seek(r, 6, 0);
print(file_read(r, 5), "\n");
file_close(r);

:see
>sys
file_tell
file_read
file_open