TECHNICAL ISO/IEC TS SPECIFICATION 18661-2 First edition 2015-02-15 Information Technology - Programming languages, their environments, and system software interfaces Floating-point extensions for C - Part 2: Decimal floating-point arithmetic Technologies de I'information Langages de programmation, leurs environnements et interfaces du logiciel systeme - Extensions a virgule flottante pour C - Partie 2: Arithmétique décimal en virgule flottante Reference number IS0/IEC TS 18661-2:2015(E) TEC International Organization for Standardization lardization5956617 IS0/IEC2015 Not for Re ithout license from IHS IS0/IECTS 18661-2:2015(E) COPYRIGHTPROTECTEDDOCUMENT @IS0/IEC2015 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 : CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland Prganizationfor Standardization icene-zZhejag nsitue o StandareRalS Ss6JEC 2015 - All rights reserved Not for Resale, 2015/6/2 06:34:33 etworking permitted without license from IHS IS0/IEC TS 18661-2:2015(E) Foreword .iv Introduction. ..V 1 Scope. ..1 2 Conformance. ..1 3 Normative references ..1 4 Terms and definitions ..1 5 C standard conformance. ..2 5.1 Freestanding implementations .2 5.2 Predefined macros. . 2 5.3 Standard headers. ..3 6 Decimal floating types ..10 7 Characteristics of decimal floating types <float.h> ..11 8 Operation binding. ..15 9 Conversions. .16 9.1 Conversions between decimal floating and integer types ..16 9.2 Conversions among decimal floating types, and between decimal floating and standard floating types ..17 9.3 Conversions between decimal floating and complex types.. ..18 9.4 Usual arithmetic conversions. .18 9.5 Default argument promotion. .18 10 Constants ..18 11 Arithmetic operations. .19 11.1 Operators. .19 11.2 Functions... 20 11.3 Conversions 21 11.4 Expression transformations 21 12 Library .21 12.1 Standard headers. 21 12.2 Decimal floating-point environment in <fenv.h> 21 12.3 Decimal mathematics in <math.h> 25 12.4 Decimal-onlyfunctionsin<math.h> 34 12.4.1Quantum and quantum exponent functions .34 12.4.2 Decimal re-encoding functions. 36 12.5 Formatted input/output specifiers. .38 12.6 strtodN functions in <stdlib.h> .40 12.7 wcstodN functions in <wchar.h> 43 12.8 strfromdN functions in <stdlib.h> .44 12.9 Type-generic math for decimal in <tgmath.h> ..45 Bibliography .50 iii vided by IHS under I ed without license from IHS Not for Resale, 2015/6/2 06:34:33