STRTOD(3C-SVR3)     RISC/os Reference Manual      STRTOD(3C-SVR3)



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

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

     double atof (str)
     char *str;

DESCRIPTION
     strtod 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.

     strtod 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 point, 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).

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

DIAGNOSTICS
     If the correct value would cause overflow, +infinity 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.

















                        Printed 11/19/92                   Page 1