Loop only the first execution
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Hello,
I am trying to create a loop in a GUI that only loops the first time the program is run through, and then skip that portion any other time it comes to it. How can I do this?
This is the code I need in the loop to execute only the first time:
connection = tcpip('127.0.0.1', 3333, 'NetworkRole', 'server'); % connect to server socket via TCP/IP
fclose(connection);%Make sure socket is closed before attempting to open port
fopen(connection);
Thanks in advance for any help!
SM
回答（1 个）
Walter Roberson
2016-11-17
persistent has_been_initialized
if isempty(has_been_initialized)
connection = tcpip('127.0.0.1', 3333, 'NetworkRole', 'server'); % connect to server socket via TCP/IP
fclose(connection);%Make sure socket is closed before attempting to open port
fopen(connection);
has_been_initialized = true;
end
Reminder: your variable connection looks like a local variable in the workspace of that function. If that local variable goes out of scope then the connection will be shut down.
2 个评论
Me29
2016-11-17
Walter Roberson
2016-11-17
See the above link on the various ways you can export information from a function.
One way would just be
persistent connection
if isempty(connection)
connection = tcpip('127.0.0.1', 3333, 'NetworkRole', 'server'); % connect to server socket via TCP/IP
fclose(connection);%Make sure socket is closed before attempting to open port
fopen(connection);
end
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2016-11-17
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