nan, nanf, nanl, nand32, nand64, nand128

Converts the implementation-defined character string arg into the corresponding quiet NaN value, as if by calling the appropriate parsing function strtoX , as follows:

• The call nan ( "n-char-sequence" ) , where n-char-sequence is a sequence of digits, Latin letters, and underscores, is equivalent to the call /*strtoX*/ ( "NAN(n-char-sequence)" , ( char ** ) NULL ) ; .
• The call nan ( "" ) is equivalent to the call /*strtoX*/ ( "NAN()" , ( char ** ) NULL ) ; .
• The call nan ( "string" ) , where string is neither an n-char-sequence nor an empty string, is equivalent to the call /*strtoX*/ ( "NAN" , ( char ** ) NULL ) ; .

Parameters

Return value

The quiet NaN value that corresponds to the identifying string arg or zero if the implementation does not support quiet NaNs.

If the implementation supports IEEE floating-point arithmetic (IEC 60559), it also supports quiet NaNs.

Error handling

This function is not subject to any of the error conditions specified in math_errhandling .

Example

#include <stdio.h>
#include <math.h>
#include <stdint.h>
#include <inttypes.h>
#include <string.h>
 
int main(void)
{
    double f1 = nan("1");
    uint64_t f1n; memcpy(&f1n, &f1, sizeof f1);
    printf("nan(\"1\")   = %f (%" PRIx64 ")\n", f1, f1n);
 
    double f2 = nan("2");
    uint64_t f2n; memcpy(&f2n, &f2, sizeof f2);
    printf("nan(\"2\")   = %f (%" PRIx64 ")\n", f2, f2n);
 
    double f3 = nan("0xF");
    uint64_t f3n; memcpy(&f3n, &f3, sizeof f3);
    printf("nan(\"0xF\") = %f (%" PRIx64 ")\n", f3, f3n);
}

nan("1")   = nan (7ff8000000000001)
nan("2")   = nan (7ff8000000000002)
nan("0xF") = nan (7ff800000000000f)

References

See also