@node IO operations
@section IO operations

Provided by module @code{(hnh util io)}.

@defun open-input-port path
@defunx open-output-port path
Like @code{open-*-file}, but ``-'' gives @code{standard-@{input,output@}}.
@end defun

@defun read-lines port
Return a list of all lines read from port.

The trailing newlines are @emph{not} part of the string.
@end defun

@defun with-atomic-output-to-file filename thunk
Same functionality as the regular @var{with-output-to-file}, but
with the difference that either everything is written, or nothing
is written, and if anything is written it's all written atomicaly at
once (the original file will never contain an intermidiate state).
Does NOT handle race conditions between threads.

propagates the return value of @var{thunk} upon successfully writing
the file, and @code{#f} otherwise.
@end defun

@defun call-with-tmpfile proc [#:tmpl ``/tmp/file-XXXXXXX'']
Creates a new temporary file, named per the template @var{tmpl}, then
call @var{proc} with two arguments: an open input-output port to the
file, and the generated name of the file.

The file will be closed upon the procedures return. However, the file
@emph{may} be left on disk.
@end defun

@defun read-file path
Open file at path, and return its content as a string.
@end defun

@defun displayln x [port]
Calls @code{display}, followed by @code{newline}.
@end defun