📄 hex-floats.html
字号:
<html lang="en"><head><title>Using the GNU Compiler Collection (GCC)</title><meta http-equiv="Content-Type" content="text/html"><meta name="description" content="Using the GNU Compiler Collection (GCC)"><meta name="generator" content="makeinfo 4.6"><!--Copyright © 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc. <p>Permission is granted to copy, distribute and/or modify this documentunder the terms of the GNU Free Documentation License, Version 1.2 orany later version published by the Free Software Foundation; with theInvariant Sections being "GNU General Public License" and "FundingFree Software", the Front-Cover texts being (a) (see below), and withthe Back-Cover Texts being (b) (see below). A copy of the license isincluded in the section entitled "GNU Free Documentation License". <p>(a) The FSF's Front-Cover Text is: <p>A GNU Manual <p>(b) The FSF's Back-Cover Text is: <p>You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.--><meta http-equiv="Content-Style-Type" content="text/css"><style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller }--></style></head><body><div class="node"><p>Node: <a name="Hex%20Floats">Hex Floats</a>,Next: <a rel="next" accesskey="n" href="Zero-Length.html#Zero%20Length">Zero Length</a>,Previous: <a rel="previous" accesskey="p" href="Complex.html#Complex">Complex</a>,Up: <a rel="up" accesskey="u" href="C-Extensions.html#C%20Extensions">C Extensions</a><hr><br></div><h3 class="section">Hex Floats</h3><p>ISO C99 supports floating-point numbers written not only in the usualdecimal notation, such as <code>1.55e1</code>, but also numbers such as<code>0x1.fp3</code> written in hexadecimal format. As a GNU extension, GCCsupports this in C89 mode (except in some cases when strictlyconforming) and in C++. In that format the<code>0x</code> hex introducer and the <code>p</code> or <code>P</code> exponent field aremandatory. The exponent is a decimal number that indicates the power of2 by which the significant part will be multiplied. Thus <code>0x1.f</code> is1 15/16,<code>p3</code> multiplies it by 8, and the value of <code>0x1.fp3</code>is the same as <code>1.55e1</code>. <p>Unlike for floating-point numbers in the decimal notation the exponentis always required in the hexadecimal notation. Otherwise the compilerwould not be able to resolve the ambiguity of, e.g., <code>0x1.f</code>. Thiscould mean <code>1.0f</code> or <code>1.9375</code> since <code>f</code> is also theextension for floating-point constants of type <code>float</code>. </body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -