VMS Help CC, Run-time functions, atof  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Converts a character string to a double-precision number.  The
  character string has the following form:

  [white-spaces][+|-]digits[radix-character][digits][e|E[+|-]integer]

  Where radix-character is defined in the current locale.

  The first unrecognized character ends the conversion.

  The string is interpreted by the same rules that are used to
  interpret floating constants.

  Syntax:

       #include <stdlib.h>

       double atof(const char *nptr);