Tutorial by Topics: input

A key component of interactive web systems, input tags are HTML elements designed to take a specific form of input from users. Different types of input elements can regulate the data entered to fit a specified format and provide security to password entry.

TextInputLayout was introduced to display the floating label on EditText. The EditText has to be wrapped by TextInputLayout in order to display the floating label.

IO may be blocking/non-blocking and synchronous/asynchronous. POSIX API provides synchronous blocking API (e.g. classic read, write, send, recv calls), synchronous non-blocking API (same functions, file descriptors opened with O_NONBLOCK flag and IO-multiplexing calls) and asynchonous API (functions starting with aio_).

Synchronous API is usually used with "one thread/process per fd" style. This is dreadful for resources. Non-blocking API allows to operate with a set of fds in one thread.

Input and Output in scheme is usually handled trough ports. A port is a data structure which is used to interact with the world outside Scheme. A Port isn't limited to files but can be used to read/write to sockets. In some ways, the port object is some kind of universal object that can not only manipulate file and sockets but any kind of read/write operation with the OS. For example, one could implement a port that can write to a printer or even control a CNC machine from Scheme using a port.

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