xref: /dragonfly/lib/libc/stdlib/strtol.3 (revision 1de703da)
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36.\"     @(#)strtol.3	8.1 (Berkeley) 6/4/93
37.\" $FreeBSD: src/lib/libc/stdlib/strtol.3,v 1.4.2.5 2001/12/14 18:33:58 ru Exp $
38.\" $DragonFly: src/lib/libc/stdlib/strtol.3,v 1.2 2003/06/17 04:26:46 dillon Exp $
39.\"
40.Dd June 4, 1993
41.Dt STRTOL 3
42.Os
43.Sh NAME
44.Nm strtol , strtoll , strtoq
45.Nd "convert a string value to a long, long long, or quad_t integer"
46.Sh LIBRARY
47.Lb libc
48.Sh SYNOPSIS
49.In stdlib.h
50.In limits.h
51.Ft long
52.Fn strtol "const char *nptr" "char **endptr" "int base"
53.Ft long long
54.Fn strtoll "const char *nptr" "char **endptr" "int base"
55.In sys/types.h
56.In stdlib.h
57.In limits.h
58.Ft quad_t
59.Fn strtoq "const char *nptr" "char **endptr" "int base"
60.Sh DESCRIPTION
61The
62.Fn strtol
63function
64converts the string in
65.Fa nptr
66to a
67.Em long
68value.
69The
70.Fn strtoll
71function
72converts the string in
73.Fa nptr
74to a
75.Em long long
76value.
77The
78.Fn strtoq
79function
80converts the string in
81.Fa nptr
82to a
83.Em quad_t
84value.
85The conversion is done according to the given
86.Fa base ,
87which must be between 2 and 36 inclusive,
88or be the special value 0.
89.Pp
90The string may begin with an arbitrary amount of white space
91(as determined by
92.Xr isspace 3 )
93followed by a single optional
94.Ql +
95or
96.Ql -
97sign.
98If
99.Fa base
100is zero or 16,
101the string may then include a
102.Ql 0x
103prefix,
104and the number will be read in base 16; otherwise, a zero
105.Fa base
106is taken as 10 (decimal) unless the next character is
107.Ql 0 ,
108in which case it is taken as 8 (octal).
109.Pp
110The remainder of the string is converted to a
111.Em long
112value in the obvious manner,
113stopping at the first character which is not a valid digit
114in the given base.
115(In bases above 10, the letter
116.Ql A
117in either upper or lower case
118represents 10,
119.Ql B
120represents 11, and so forth, with
121.Ql Z
122representing 35.)
123.Pp
124If
125.Fa endptr
126is non nil,
127.Fn strtol
128stores the address of the first invalid character in
129.Fa *endptr .
130If there were no digits at all, however,
131.Fn strtol
132stores the original value of
133.Fa nptr
134in
135.Fa *endptr .
136(Thus, if
137.Fa *nptr
138is not
139.Ql \e0
140but
141.Fa **endptr
142is
143.Ql \e0
144on return, the entire string was valid.)
145.Sh RETURN VALUES
146The
147.Fn strtol
148function
149returns the result of the conversion,
150unless the value would underflow or overflow.
151If an underflow occurs,
152.Fn strtol
153returns
154.Dv LONG_MIN .
155If an overflow occurs,
156.Fn strtol
157returns
158.Dv LONG_MAX .
159The
160.Fn strtoll
161function
162returns the result of the conversion,
163unless the value would underflow or overflow.
164If an underflow occurs,
165.Fn strtoll
166returns
167.Dv LLONG_MIN .
168If an overflow occurs,
169.Fn strtoll
170returns
171.Dv LLONG_MAX .
172In all cases,
173.Va errno
174is set to
175.Er ERANGE .
176.Sh ERRORS
177.Bl -tag -width Er
178.It Bq Er ERANGE
179The given string was out of range; the value converted has been clamped.
180.El
181.Sh SEE ALSO
182.Xr atof 3 ,
183.Xr atoi 3 ,
184.Xr atol 3 ,
185.Xr strtod 3 ,
186.Xr strtoul 3
187.Sh STANDARDS
188The
189.Fn strtol
190function
191conforms to
192.St -isoC .
193The
194.Fn strtoll
195function
196conforms to
197.St -isoC-99 .
198The
199.Bx
200.Fn strtoq
201function is deprecated.
202.Sh BUGS
203Ignores the current locale.
204