November 2016
Beginner to intermediate
816 pages
19h 58m
Japanese
Content preview from Cクイックリファレンス 第2版
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
62
5
章 式と演算子
5.1
式の評価法
演算子の詳細を取り上げる前に、本節で、Cが式をどのように評価するか理解するのに
役立つ基本原則を説明する。演算子の優先度と結合性は明らかに複合式のパースに重要だ
が、総称選択、
lvalue
、副作用完了点もCプログラムがどのように動作するかを理解する
のに同じほど本質的だ。
5.1.1
総称選択（
C11
）
総称選択は、他の式の型に依存するリストから式を選ぶ基本式である。選択はコンパイ
ル時に行われる。この機構でC開発者は、C99標準で導入されたヘッダtgmath.hが提供す
る数学関数用のような型総称（ジェネリック）マクロを書くことができる。例えば、tgmath.
hは 6つの異なる平方根関数を用意する。そのうち3つは
float
,
double
,
long double
用で、
いずれも対応する複素型用だ。ヘッダtgmath.hを含むプログラムでは、
x
の型に合う関数
を自動的に呼び出す型総称マクロ
sqrt(x)
が使える。
総称選択は新キーワード
_Generic
の後ろに括弧で括った制御式と総称関連のリストが続
く。
_Generic(
expression
, generic association 1
[, generic association 2, ...])
総称関連は、
type name :
expression
または
default :
expression
の形式である。
default
関連はオプションで、このリストに2回以上出現してはいけない。
型名は、異なった相互に適 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.