Delphi knowledge points and technology Overview [Chapter 2 Runtime Library (RTL )]

Abstract:

* RTL Overview

The Runtime Library (RTL) is a very large collection of functions.

RTL Unit

Sysutils and sysconst units

The sysconst Unit defines constant strings that display messages by other RTL units. These strings are declared with the resourcestring keyword and saved in program resources. Some of its features are frequently used, such as inttostr, format, and Windows version information.

Time and date operations do not cause exceptions.

Trystrtodate: Convert string to date

Tryencodedate: encode the date

Tryencodetime: encode the time

Decodedatefully returns the day of the week

The curentyear function returns the date of today.

Math mathematical Unit

Infinity and neginfinity infinity Constants

Comparison functions isinfinite and isnan

Ifthen is equivalent to the three-object operation in C, Min: = ifthen (Na <AB, Na, Nb );

Randomrange returns a random value between two specified extreme values.

Randomfrom selects a value from an array of possible values (passed to it as a parameter)

Isrange returns a Boolean value to check whether the value is between two numbers.

Ensurerange forces a value between the specified range. If you return yourself or the upper or lower limit out of the range

Samevalue is used for floating point correlation to compare whether the two values are close enough.

Iszero compares whether a value is 0

Divmod returns the multiplication and remainder values at a time.

Roundto allows you to specify the rounding position

Convutils and stdconvs units

Set of unit conversion functions

Dateutils Unit

Set of Date and Time Functions

Strutils Unit

String-related functions

Ansiindextext String Array search

Ansicontainstext string Positioning

Ansireplacetext text substitution

When multiple strings exist in another string.

Types Unit

A Pascal File

Delphimm and sharemem units

Related to memory management

Com-related units

Comconts, comobj, and comserv provide low-level com support. But it does not belong to RTL.

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* Conversion Engine

In the stdconvs Unit

Convert (31, tucelsius, tufahrenheit); converts 31 degrees Celsius to Fahrenheit

Convert (20, dummies, tuhours, dwmeters, tuseconds); converts the hourly mileage to the meter per second.

* Data, strings, and other new RTL units

Sysutils File Management

* Tobject class

The mother of the Delphi class.

The sender parameter of the event processing function is of the tobject type. This means that the sender object can belong to any class.

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