Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
STRTOD(3)		   Library Functions Manual		     STRTOD(3)

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, using string_to_deci-
       mal(3), with fortran_conventions	set to 0.

       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	for historical compat-
       ibility,	 0.0  is  returned, although a NaN would better	match the IEEE
       Floating-Point Standard's intent.

       The radix character is defined by the program's locale (category	LC_NU-
       MERIC).	In the "C" locale, or in a locale where	the radix character is
       not defined.  the radix character defaults to a period `.'.

       atof(str) is equivalent to  strtod(str,	(char  **)NULL).   Thus,  when
       atof(str)  returns  0.0	there  is no way to determine whether str con-
       tained a	valid numerical	string representing 0.0	or an invalid  numeri-
       cal string.

SEE ALSO
       scanf(3V), string_to_decimal(3)

DIAGNOSTICS
       Exponent	 overflow  and	underflow produce the results specified	by the
       IEEE Standard.  In addition, errno is set to ERANGE.

				5 October 1989			     STRTOD(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | DIAGNOSTICS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=strtod&sektion=3&manpath=SunOS+4.1.3>

home | help