1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- Copyright (C) 1988-2021 Free Software Foundation, Inc. 4 5Permission is granted to copy, distribute and/or modify this document 6under the terms of the GNU Free Documentation License, Version 1.3 or 7any later version published by the Free Software Foundation; with the 8Invariant Sections being "Free Software" and "Free Software Needs 9Free Documentation", with the Front-Cover Texts being "A GNU Manual," 10and with the Back-Cover Texts as in (a) below. 11 12(a) The FSF's Back-Cover Text is: "You are free to copy and modify 13this GNU Manual. 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When used in an 78expression, a constant is interpreted to be type-compatible with the 79rest of the expression. Hexadecimal integers are specified by a 80trailing ‘<samp>H</samp>’, and octal integers by a trailing ‘<samp>B</samp>’. 81 82</li><li> Floating point constants appear as a sequence of digits, followed by a 83decimal point and another sequence of digits. An optional exponent can 84then be specified, in the form ‘<samp>E<span class="roman">[</span>+<span class="roman">|</span>-<span class="roman">]</span><var>nnn</var></samp>’, where 85‘<samp><span class="roman">[</span>+<span class="roman">|</span>-<span class="roman">]</span><var>nnn</var></samp>’ is the desired exponent. All of the 86digits of the floating point constant must be valid decimal (base 10) 87digits. 88 89</li><li> Character constants consist of a single character enclosed by a pair of 90like quotes, either single (<code>'</code>) or double (<code>"</code>). They may 91also be expressed by their ordinal value (their <small>ASCII</small> value, usually) 92followed by a ‘<samp>C</samp>’. 93 94</li><li> String constants consist of a sequence of characters enclosed by a 95pair of like quotes, either single (<code>'</code>) or double (<code>"</code>). 96Escape sequences in the style of C are also allowed. See <a href="C-Constants.html#C-Constants">C and C<tt>++</tt> Constants</a>, for a brief explanation of escape 97sequences. 98 99</li><li> Enumerated constants consist of an enumerated identifier. 100 101</li><li> Boolean constants consist of the identifiers <code>TRUE</code> and 102<code>FALSE</code>. 103 104</li><li> Pointer constants consist of integral values only. 105 106</li><li> Set constants are not yet supported. 107</li></ul> 108 109 110 111 112</body> 113</html> 114