nan, nanf, nanl - return 'Not a Number'
double nan(const char *tagp);
float nanf(const char *tagp);
long double nanl(const char *tagp);
Link with -lm.
nan(), nanf(), nanl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
These functions return a representation (determined by tagp) of a quiet
NaN. If the implementation does not support quiet NaNs, these functions return
The call nan("char-sequence") is equivalent
Similarly, calls to nanf() and nanl() are equivalent
to analogous calls to strtof(3) and strtold(3).
The argument tagp is used in an unspecified manner. On IEEE
754 systems, there are many representations of NaN, and tagp selects
one. On other systems it may do nothing.
These functions first appeared in glibc in version 2.1.
For an explanation of the terms used in this section, see attributes(7).
C99, POSIX.1-2001, POSIX.1-2008. See also IEC 559 and the appendix with
recommended functions in IEEE 754/IEEE 854.
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|nan (), nanf (), nanl ()