| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| <!-- Copyright (C) 1988-2015 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 or |
| any later version published by the Free Software Foundation; with the |
| Invariant Sections being "Funding Free Software", the Front-Cover |
| Texts being (a) (see below), and with the Back-Cover Texts being (b) |
| (see below). A copy of the license is included in the section entitled |
| "GNU Free Documentation License". |
| |
| (a) The FSF's Front-Cover Text is: |
| |
| A GNU Manual |
| |
| (b) The FSF's Back-Cover Text is: |
| |
| 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. --> |
| <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ --> |
| <head> |
| <title>Using the GNU Compiler Collection (GCC): Long Long</title> |
| |
| <meta name="description" content="Using the GNU Compiler Collection (GCC): Long Long"> |
| <meta name="keywords" content="Using the GNU Compiler Collection (GCC): Long Long"> |
| <meta name="resource-type" content="document"> |
| <meta name="distribution" content="global"> |
| <meta name="Generator" content="makeinfo"> |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> |
| <link href="index.html#Top" rel="start" title="Top"> |
| <link href="Option-Index.html#Option-Index" rel="index" title="Option Index"> |
| <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> |
| <link href="C-Extensions.html#C-Extensions" rel="up" title="C Extensions"> |
| <link href="Complex.html#Complex" rel="next" title="Complex"> |
| <link href="_005f_005fint128.html#g_t_005f_005fint128" rel="prev" title="__int128"> |
| <style type="text/css"> |
| <!-- |
| a.summary-letter {text-decoration: none} |
| blockquote.smallquotation {font-size: smaller} |
| div.display {margin-left: 3.2em} |
| div.example {margin-left: 3.2em} |
| div.indentedblock {margin-left: 3.2em} |
| div.lisp {margin-left: 3.2em} |
| div.smalldisplay {margin-left: 3.2em} |
| div.smallexample {margin-left: 3.2em} |
| div.smallindentedblock {margin-left: 3.2em; font-size: smaller} |
| div.smalllisp {margin-left: 3.2em} |
| kbd {font-style:oblique} |
| pre.display {font-family: inherit} |
| pre.format {font-family: inherit} |
| pre.menu-comment {font-family: serif} |
| pre.menu-preformatted {font-family: serif} |
| pre.smalldisplay {font-family: inherit; font-size: smaller} |
| pre.smallexample {font-size: smaller} |
| pre.smallformat {font-family: inherit; font-size: smaller} |
| pre.smalllisp {font-size: smaller} |
| span.nocodebreak {white-space:nowrap} |
| span.nolinebreak {white-space:nowrap} |
| span.roman {font-family:serif; font-weight:normal} |
| span.sansserif {font-family:sans-serif; font-weight:normal} |
| ul.no-bullet {list-style: none} |
| --> |
| </style> |
| |
| |
| </head> |
| |
| <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> |
| <a name="Long-Long"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="Complex.html#Complex" accesskey="n" rel="next">Complex</a>, Previous: <a href="_005f_005fint128.html#g_t_005f_005fint128" accesskey="p" rel="prev">__int128</a>, Up: <a href="C-Extensions.html#C-Extensions" accesskey="u" rel="up">C Extensions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> |
| </div> |
| <hr> |
| <a name="Double_002dWord-Integers"></a> |
| <h3 class="section">6.9 Double-Word Integers</h3> |
| <a name="index-long-long-data-types"></a> |
| <a name="index-double_002dword-arithmetic"></a> |
| <a name="index-multiprecision-arithmetic"></a> |
| <a name="index-LL-integer-suffix"></a> |
| <a name="index-ULL-integer-suffix"></a> |
| |
| <p>ISO C99 supports data types for integers that are at least 64 bits wide, |
| and as an extension GCC supports them in C90 mode and in C++. |
| Simply write <code>long long int</code> for a signed integer, or |
| <code>unsigned long long int</code> for an unsigned integer. To make an |
| integer constant of type <code>long long int</code>, add the suffix ‘<samp>LL</samp>’ |
| to the integer. To make an integer constant of type <code>unsigned long |
| long int</code>, add the suffix ‘<samp>ULL</samp>’ to the integer. |
| </p> |
| <p>You can use these types in arithmetic like any other integer types. |
| Addition, subtraction, and bitwise boolean operations on these types |
| are open-coded on all types of machines. Multiplication is open-coded |
| if the machine supports a fullword-to-doubleword widening multiply |
| instruction. Division and shifts are open-coded only on machines that |
| provide special support. The operations that are not open-coded use |
| special library routines that come with GCC. |
| </p> |
| <p>There may be pitfalls when you use <code>long long</code> types for function |
| arguments without function prototypes. If a function |
| expects type <code>int</code> for its argument, and you pass a value of type |
| <code>long long int</code>, confusion results because the caller and the |
| subroutine disagree about the number of bytes for the argument. |
| Likewise, if the function expects <code>long long int</code> and you pass |
| <code>int</code>. The best way to avoid such problems is to use prototypes. |
| </p> |
| |
| |
| |
| </body> |
| </html> |
