46 lines
2.1 KiB
XML
46 lines
2.1 KiB
XML
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<?xml version="1.0"?>
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<clause number="25.5.2" title="Pointer member access">
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<paragraph>A <non_terminal where="25.5.2">pointer-member-access</non_terminal> consists of a <non_terminal where="14.5">primary-expression</non_terminal>, followed by a "->" token, followed by an identifier. <grammar_production><name><non_terminal where="25.5.2">pointer-member-access</non_terminal></name> : <rhs><non_terminal where="14.5">primary-expression</non_terminal><terminal>-></terminal><non_terminal where="9.4.2">identifier</non_terminal></rhs></grammar_production></paragraph>
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<paragraph>In a pointer member access of the form P->I, P must be an expression of a pointer type other than void*, and I must denote an accessible member of the type to which P points. </paragraph>
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<paragraph>A pointer member access of the form P->I is evaluated exactly as (*P).I. For a description of the pointer indirection operator (*), see <hyperlink>25.5.1</hyperlink>. For a description of the member access operator (.), see <hyperlink>14.5.4</hyperlink>. </paragraph>
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<paragraph>
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<example>[Example: In the example <code_example><![CDATA[
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struct Point
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{
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public int x;
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public int y;
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public override string ToString() {
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return "(" + x + "," + y + ")";
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}
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}
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using System;
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class Test
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{
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static void Main() {
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Point point;
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unsafe {
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Point* p = &point;
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p->x = 10;
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p->y = 20;
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Console.WriteLine(p->ToString());
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}
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}
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}
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]]></code_example>the -> operator is used to access fields and invoke a method of a struct through a pointer. Because the operation P->I is precisely equivalent to (*P).I, the Main method could equally well have been written: <code_example><![CDATA[
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using System;
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class Test
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{
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static void Main() {
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Point point;
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unsafe {
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Point* p = &point;
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(*p).x = 10;
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(*p).y = 20;
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Console.WriteLine((*p).ToString());
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}
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}
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}
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]]></code_example>end example]</example>
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</paragraph>
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</clause>
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