STRTOD(3C) (C Programming Language Utilities) 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
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, +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.
Page 1 May 1989