zZzzZ. — /usr/include/bits

Editing: stdlib-float.h

/* Floating-point inline functions for stdlib.h.
   Copyright (C) 2012-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#ifndef _STDLIB_H
# error "Never use <bits/stdlib-float.h> directly; include <stdlib.h> instead."
#endif

#ifdef __USE_EXTERN_INLINES
__extern_inline double
__NTH (atof (const char *__nptr))
{
  return strtod (__nptr, (char **) NULL);
}
#endif /* Optimizing and Inlining.  */