strtod(3C)           INTERACTIVE UNIX System           strtod(3C)



          NAME
               strtod, atof - convert string to double-precision number

          SYNOPSIS
               double strtod (str, ptr)
               char *str, **ptr;

               double atof (str)
               char *str;

          DESCRIPTION
               The strtod function returns as a double-precision floating-
               point number the value represented by the character string
               pointed to by str.  The string is scanned up to the first
               unrecognized character.

               The strtod function recognizes an optional string of
               ``white-space'' characters [as defined by isspace in
               ctype(3C)], then an optional sign, then a string of digits
               optionally containing a decimal delimiter, then an optional
               e or E followed by an optional sign or space, followed by an
               integer.

               If the value of ptr is not (char **)NULL, a pointer to the
               character terminating the scan is returned in the location
               pointed to by ptr.  If no number can be formed, *ptr is set
               to str, and zero is returned.

               atof(str) is equivalent to strtod(str, (char **)NULL).

               In the POSIX environment, the decimal delimiter depends on
               the current locale.

          SEE ALSO
               ctype(3C), scanf(3S), strtol(3C), locale(5P).

          DIAGNOSTICS
               If the correct value would cause overflow, +HUGE (as defined
               in <math.h>) is returned (according to the sign of the
               value), and errno is set to ERANGE.
               If the correct value would cause underflow, zero is returned
               and errno is set to ERANGE.













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