Limit for gsl_sf_erf

[Jackson Vanover]

Using version 2.6 of GSL from ftp://ftp.gnu.org/gnu/gsl/gsl-2.6.tar.gz

OS is Ubuntu 18.04.2 LTS

Hardware is a Dell workstation with a 3.60 GHz Intel i7-4790 and 32 GB
of RAM

Compiler is gcc 7.4.0 with the -w option

When evaluating gsl_sf_erf(inf), a NaN is returned even though the limit
approaches 1. I bring this up as an issue because in other cases, the
special functions in the library handle such limits approaching infinity
properly, e.g. gsl_sf_eta(inf) returns 1.

#include <gsl/gsl_sf.h>
#include <stdio.h>
#include <gsl/gsl_math.h>

int main (void){
double out;
out = gsl_sf_erf(GSL_POSINF);

printf("%f\n", out);
printf("%.21e\n", out);
return 0;
}

Best,
Jackson Vanover