nan

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Langue: ja

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Version: 2002-08-10 (openSuse - 09/10/07)

Section: 3 (Bibliothèques de fonctions)

Sommaire

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nan, nanf, nanl - ̵¸úÃÍ ('Not a Number') ¤òÊÖ¤¹

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#include <math.h>

double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);

-std=c99 ¤Ç¥³¥ó¥Ñ¥¤¥ë¤·¡¢-lm ¤Ç¥ê¥ó¥¯¤¹¤ë¡£

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¤³¤ì¤é¤Î´Ø¿ô¤Ï¡¢SIGFPE ¥·¥°¥Ê¥ë¤Ê¤·¤Î̵¸úÃÍ (NaN) ¤ò¼¨¤¹É½¸½¤òÊÖ¤¹ (¤É¤Îɽ¸½¤ò»ÈÍѤ¹¤ë¤«¤Ï tagp ¤Ç»ØÄꤹ¤ë)¡£SIGFPE ¥·¥°¥Ê¥ë¤Ê¤·¤Î NaN ¤ò¥µ¥Ý¡¼¥È¤·¤Æ¤¤¤Ê¤¤¼ÂÁõ¤Ç¤Ï 0 ¤òÊÖ¤¹¡£

nan(char-sequence) ¤ò¸Æ¤Ó½Ð¤¹¤Î¤Ï¡¢ strtod (NAN(char-sequence),NULL) ¤ÈÅù²Á¤Ç¤¢¤ë¡£ ƱÍͤˡ¢ nanf() ¤ä nanl() ¤ò¸Æ¤Ó½Ð¤¹¤Î¤Ï¡¢ strtof() ¤ä strtold() ¤ò¸Æ¤Ö¤Î¤ÈƱ¤¸¤Ç¤¢¤ë¡£

°ú¤­¿ô tagp ¤Î»È¤¤Êý¤Ïµ¬Äꤵ¤ì¤Æ¤¤¤Ê¤¤¡£ IEEE 754 ½àµò¤Î¥·¥¹¥Æ¥à¤Ç¤Ï¡¢NaN ¤Ë¤âÊ£¿ô¤Îɽ¸½¤¬Â¸ºß¤·¡¢ tagp ¤Ï¤½¤ÎÁªÂò¤Ë»ÈÍѤµ¤ì¤ë¡£ ¾¤Î¥·¥¹¥Æ¥à¤Ç¤Ï¡¢²¿¤Î°ÕÌ£¤â¤Ê¤¤¤«¤â¤·¤ì¤Ê¤¤¡£

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C99¡£¤Þ¤¿¡¢IEC 559 ¤ä¿ä¾©´Ø¿ô¤Ë¤Ê¤Ã¤Æ¤¤¤ë IEEE 754/IEEE 854 ¤ÎÉÕÏ¿¤â»²¾È¤¹¤ë¤³¤È¡£

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isnan(3), strtod(3)