#!/usr/bin/perl -w

use strict;

my @buf = <DATA>;
chomp @buf; # chop of all the line endings

my $doc = join ' ', @buf; # one nice juicy line
my $doc_id = qr(\d+\.\d+\.); # precomp regex - also self documenting

while ($doc =~ /($doc_id)\s+(\w+)(.*?)Prototype:.*?(?=$doc_id)?/g) {
    print "$1 $2 $3\n";
}

__DATA__
5.1. GetAFunctionHere
This is the description of a function
Which spans a few lines
Prototype:
int
GetAFunctionHere(int *count)

Parameters:
*count probably some kind of spelling object

5.2. GetMoreFunctionsHere
This is the description of another function
Which spans a few more lines
Prototype:
int
GetMoreFunctionHere(float *crash)

Parameters:
*crash probably some kind of rowing object