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STRTOD(3)	       FreeBSD Library Functions Manual		     STRTOD(3)

NAME
     strtod, strtof, strtold --	convert	ASCII string to	floating point

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <stdlib.h>

     double
     strtod(const char * restrict nptr,	char **	restrict endptr);

     float
     strtof(const char * restrict nptr,	char **	restrict endptr);

     long double
     strtold(const char	* restrict nptr, char ** restrict endptr);

DESCRIPTION
     These conversion functions	convert	the initial portion of the string
     pointed to	by nptr	to double, float, and long double representation,
     respectively.

     The expected form of the string is	an optional plus (``+'') or minus sign
     (``-'') followed by either:

     +o	 a decimal significand consisting of a sequence	of decimal digits
	 optionally containing a decimal-point character, or

     +o	 a hexadecimal significand consisting of a ``0X'' or ``0x'' followed
	 by a sequence of hexadecimal digits optionally	containing a decimal-
	 point character.

     In	both cases, the	significand may	be optionally followed by an exponent.
     An	exponent consists of an	``E'' or ``e'' (for decimal constants) or a
     ``P'' or ``p'' (for hexadecimal constants), followed by an	optional plus
     or	minus sign, followed by	a sequence of decimal digits.  For decimal
     constants,	the exponent indicates the power of 10 by which	the signifi-
     cand should be scaled.  For hexadecimal constants,	the scaling is instead
     done by powers of 2.

     Alternatively, if the portion of the string following the optional	plus
     or	minus sign begins with ``INFINITY'' or ``NAN'',	ignoring case, it is
     interpreted as an infinity	or a quiet NaN,	respectively.

     In	any of the above cases,	leading	white-space characters in the string
     (as defined by the	isspace(3) function) are skipped.  The decimal point
     character is defined in the program's locale (category LC_NUMERIC).

RETURN VALUES
     The strtod(), strtof(), and strtold() functions return the	converted
     value, if any.

     If	endptr is not NULL, a pointer to the character after the last charac-
     ter used in the conversion	is stored in the location referenced by
     endptr.

     If	no conversion is performed, zero is returned and the value of nptr is
     stored in the location referenced by endptr.

     If	the correct value would	cause overflow,	plus or	minus HUGE_VAL,
     HUGE_VALF,	or HUGE_VALL is	returned (according to the sign	and type of
     the return	value),	and ERANGE is stored in	errno.	If the correct value
     would cause underflow, zero is returned and ERANGE	is stored in errno.

ERRORS
     [ERANGE]		Overflow or underflow occurred.

SEE ALSO
     atof(3), atoi(3), atol(3),	strtol(3), strtoul(3), wcstod(3)

STANDARDS
     The strtod() function conforms to ISO/IEC 9899:1999 (``ISO	C99''),	with
     the exception of the bug noted below.

AUTHORS
     The author	of this	software is David M. Gay.

     Copyright (c) 1998	by Lucent Technologies
     All Rights	Reserved

     Permission	to use,	copy, modify, and distribute this software and
     its documentation for any purpose and without fee is hereby
     granted, provided that the	above copyright	notice appear in all
     copies and	that both that the copyright notice and	this
     permission	notice and warranty disclaimer appear in supporting
     documentation, and	that the name of Lucent	or any of its entities
     not be used in advertising	or publicity pertaining	to
     distribution of the software without specific, written prior
     permission.

     LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
     INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
     IN	NO EVENT SHALL LUCENT OR ANY OF	ITS ENTITIES BE	LIABLE FOR ANY
     SPECIAL, INDIRECT OR CONSEQUENTIAL	DAMAGES	OR ANY DAMAGES
     WHATSOEVER	RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
     IN	AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
     ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
     THIS SOFTWARE.

BUGS
     These routines do not recognize the C99 ``NaN(...)'' syntax.

FreeBSD	10.1			 March 2, 2003			  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | ERRORS | SEE ALSO | STANDARDS | AUTHORS | BUGS

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