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 spaces, 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(3), scanf(3S), strtol(3). 

DIAGNOSTICS

If the correct value would cause overflow, ±HUGE 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. 

Sun Release 3.2  —  Last change:  30 April 1986