The formline keyword

formline is an internal function that is used by format, but can be used directly. It formats a LIST of values according to PICTURE, and placing the output to the $^A variable (or $ACCUMULATOR in English).

Perl attempts to flush all opened files for output before forking the child process, but this may not be supported on some platforms. To be safe, you may need to set $| ($AUTOFLUSH in English) or call the autoflush() method of IO::Handle on all open handles so that duplicate output is avoided. It is called by format once per form line.

  formline PICTURE, LIST