diff options
| -rw-r--r-- | lib/libc/stdlib/strtod.3 | 107 |
1 files changed, 75 insertions, 32 deletions
diff --git a/lib/libc/stdlib/strtod.3 b/lib/libc/stdlib/strtod.3 index ab78083ca5e7..b7b8f377add7 100644 --- a/lib/libc/stdlib/strtod.3 +++ b/lib/libc/stdlib/strtod.3 @@ -36,37 +36,65 @@ .\" @(#)strtod.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD$ .\" -.Dd June 4, 1993 +.Dd March 2, 2003 .Dt STRTOD 3 .Os .Sh NAME -.Nm strtod +.Nm strtod , strtof , strtold .Nd convert .Tn ASCII -string to double +string to floating point .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In stdlib.h .Ft double .Fn strtod "const char * restrict nptr" "char ** restrict endptr" +.Ft float +.Fn strtof "const char * restrict nptr" "char ** restrict endptr" +.Ft long double +.Fn strtold "const char * restrict nptr" "char ** restrict endptr" .Sh DESCRIPTION -The -.Fn strtod -function converts the initial portion of the string +These conversion +functions convert the initial portion of the string pointed to by .Fa nptr to -.Vt double -representation. +.Vt double , +.Vt float , +and +.Vt long double +representation, respectively. .Pp The expected form of the string is an optional plus (``+'') or minus -sign (``\-'') followed by a sequence of digits optionally containing -a decimal-point character, optionally followed by an exponent. -An exponent consists of an ``E'' or ``e'', followed by an optional plus -or minus sign, followed by a sequence of digits. +sign (``\-'') followed by either: +.Bl -bullet +.It +a decimal significand consisting of a sequence of decimal digits +optionally containing a decimal-point character, or +.It +a hexadecimal significand consisting of a ``0X'' or ``0x'' followed +by a sequence of hexadecimal digits optionally containing a +decimal-point character. +.El +.Pp +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 significand should be scaled. +For hexadecimal constants, the scaling is instead done by powers +of 2. .Pp -Leading white-space characters in the string (as defined by the +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. +.Pp +In any of the above cases, leading white-space characters in the +string (as defined by the .Xr isspace 3 function) are skipped. The decimal point @@ -74,8 +102,11 @@ character is defined in the program's locale (category .Dv LC_NUMERIC ) . .Sh RETURN VALUES The -.Fn strtod -function returns the converted value, if any. +.Fn strtod , +.Fn strtof , +and +.Fn strtold +functions return the converted value, if any. .Pp If .Fa endptr @@ -91,8 +122,11 @@ is stored in the location referenced by .Fa endptr . .Pp If the correct value would cause overflow, plus or minus -.Dv HUGE_VAL -is returned (according to the sign of the value), and +.Dv HUGE_VAL , +.Dv HUGE_VALF , +or +.Dv HUGE_VALL +is returned (according to the sign and type of the return value), and .Er ERANGE is stored in .Va errno . @@ -118,24 +152,33 @@ The .Fn strtod function conforms to -.St -isoC . +.St -isoC-99 , +with the exception of the bug noted below. +.Sh BUGS +These routines do not recognize the C99 ``NaN(...)'' syntax. .Sh AUTHORS The author of this software is .An David M. Gay . .Pp -Copyright (c) 1991 by AT&T. +Copyright (c) 1998 by Lucent Technologies +.br +All Rights Reserved .Pp -Permission to use, copy, modify, and distribute this software for any -purpose without fee is hereby granted, provided that this entire notice -is included in all copies of any software which is or includes a copy -or modification of this software and in all copies of the supporting -documentation for such software. +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. .Pp -THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED -WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY -REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY -OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. -.Pp -Contact your vendor for a free copy of the source code to -.Fn strtod -and accompanying functions. +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. |