xref: /freebsd/lib/libc/stdlib/strtol.3 (revision c678bc4f13a340ad88debe321afd0097db2590cb)
1.\" Copyright (c) 1990, 1991, 1993
2.\"	The Regents of the University of California.  All rights reserved.
3.\"
4.\" This code is derived from software contributed to Berkeley by
5.\" Chris Torek and the American National Standards Committee X3,
6.\" on Information Processing Systems.
7.\"
8.\" Redistribution and use in source and binary forms, with or without
9.\" modification, are permitted provided that the following conditions
10.\" are met:
11.\" 1. Redistributions of source code must retain the above copyright
12.\"    notice, this list of conditions and the following disclaimer.
13.\" 2. Redistributions in binary form must reproduce the above copyright
14.\"    notice, this list of conditions and the following disclaimer in the
15.\"    documentation and/or other materials provided with the distribution.
16.\" 3. All advertising materials mentioning features or use of this software
17.\"    must display the following acknowledgement:
18.\"	This product includes software developed by the University of
19.\"	California, Berkeley and its contributors.
20.\" 4. Neither the name of the University nor the names of its contributors
21.\"    may be used to endorse or promote products derived from this software
22.\"    without specific prior written permission.
23.\"
24.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34.\" SUCH DAMAGE.
35.\"
36.\"     @(#)strtol.3	8.1 (Berkeley) 6/4/93
37.\" $FreeBSD$
38.\"
39.Dd June 4, 1993
40.Dt STRTOL 3
41.Os
42.Sh NAME
43.Nm strtol , strtoll , strtoq
44.Nd "convert a string value to a long, long long, or quad_t integer"
45.Sh LIBRARY
46.Lb libc
47.Sh SYNOPSIS
48.Fd #include <stdlib.h>
49.Fd #include <limits.h>
50.Ft long
51.Fn strtol "const char *nptr" "char **endptr" "int base"
52.Ft long long
53.Fn strtoll "const char *nptr" "char **endptr" "int base"
54.Fd #include <sys/types.h>
55.Fd #include <stdlib.h>
56.Fd #include <limits.h>
57.Ft quad_t
58.Fn strtoq "const char *nptr" "char **endptr" "int base"
59.Sh DESCRIPTION
60The
61.Fn strtol
62function
63converts the string in
64.Fa nptr
65to a
66.Em long
67value.
68The
69.Fn strtoll
70function
71converts the string in
72.Fa nptr
73to a
74.Em long long
75value.
76The
77.Fn strtoq
78function
79converts the string in
80.Fa nptr
81to a
82.Em quad_t
83value.
84The conversion is done according to the given
85.Fa base ,
86which must be between 2 and 36 inclusive,
87or be the special value 0.
88.Pp
89The string may begin with an arbitrary amount of white space
90(as determined by
91.Xr isspace 3 )
92followed by a single optional
93.Ql +
94or
95.Ql -
96sign.
97If
98.Fa base
99is zero or 16,
100the string may then include a
101.Ql 0x
102prefix,
103and the number will be read in base 16; otherwise, a zero
104.Fa base
105is taken as 10 (decimal) unless the next character is
106.Ql 0 ,
107in which case it is taken as 8 (octal).
108.Pp
109The remainder of the string is converted to a
110.Em long
111value in the obvious manner,
112stopping at the first character which is not a valid digit
113in the given base.
114(In bases above 10, the letter
115.Ql A
116in either upper or lower case
117represents 10,
118.Ql B
119represents 11, and so forth, with
120.Ql Z
121representing 35.)
122.Pp
123If
124.Fa endptr
125is non nil,
126.Fn strtol
127stores the address of the first invalid character in
128.Fa *endptr .
129If there were no digits at all, however,
130.Fn strtol
131stores the original value of
132.Fa nptr
133in
134.Fa *endptr .
135(Thus, if
136.Fa *nptr
137is not
138.Ql \e0
139but
140.Fa **endptr
141is
142.Ql \e0
143on return, the entire string was valid.)
144.Sh RETURN VALUES
145The
146.Fn strtol
147function
148returns the result of the conversion,
149unless the value would underflow or overflow.
150If an underflow occurs,
151.Fn strtol
152returns
153.Dv LONG_MIN .
154If an overflow occurs,
155.Fn strtol
156returns
157.Dv LONG_MAX .
158The
159.Fn strtoll
160function
161returns the result of the conversion,
162unless the value would underflow or overflow.
163If an underflow occurs,
164.Fn strtoll
165returns
166.Dv LLONG_MIN .
167If an overflow occurs,
168.Fn strtoll
169returns
170.Dv LLONG_MAX .
171In all cases,
172.Va errno
173is set to
174.Er ERANGE .
175.Sh ERRORS
176.Bl -tag -width Er
177.It Bq Er ERANGE
178The given string was out of range; the value converted has been clamped.
179.El
180.Sh SEE ALSO
181.Xr atof 3 ,
182.Xr atoi 3 ,
183.Xr atol 3 ,
184.Xr strtod 3 ,
185.Xr strtoul 3
186.Sh STANDARDS
187The
188.Fn strtol
189function
190conforms to
191.St -isoC .
192The
193.Fn strtoll
194function
195conforms to
196.St -isoC-99 .
197The
198.Bx
199.Fn strtoq
200function is deprecated.
201.Sh BUGS
202Ignores the current locale.
203