nan()

Converts a character string to not-a-number.

  #include <math.h>
  
  double nan(const char *tagp);
  
  float nanf(const char *tagp);
  
  long double nanl(const char *tagp);

Parameter

tagp

A pointer to a character string.

Remarks

A quiet NAN is returned, if available.

This facility may not be available on configurations of the EWL that run on platforms that do not have floating-point math capabilities.

Listing: Example of copysign() usage


#include <math.h>

#include <stdio.h>

int main(void)

{

double e = +10.0;

double f = -3.0;

printf("Copysign(%f, %f) = %f.\n", e, f, copysign(e,f));

return 0;

}

Output:

Copysign(10.000000, -3.000000) = -10.000000.