read.m

来自「王小平《遗传算法——理论、应用与软件实现》随书光盘」· M 代码 · 共 53 行

function [out,success]=read(filename,old,retries);
%
% function to wait for the next reading to become available
%
% [out]=read(filename,old,retries)
%
% out = returned process vector
% old = previous index of process vector
% filename = name of the transfer file
% success = 1 for OK read
% success = -1 for timeout
% retries = number of attempts to get the data 
%

out=[];
success=-1;

%
% Wait until file becomes available
%
cd d:
for i = 1:retries
	%
	% Wait for 0.25 secs
	%
	tic;
	while toc < 0.1
		drawnow;
	end

	fid=fopen('transfer.dat','r');
	drawnow;
	%
	% Pause for a tad
	%
	if fid ~= -1
		fclose(fid);
		tic;
		while toc < 0.1
			drawnow;
		end
		load transfer.dat
		if sum(transfer) ~= sum(old)
			out=transfer;
			success=1;
			break;
		end
	end

end