xref: /dragonfly/lib/libc/stdlib/strtol.3 (revision 1847e88f)
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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 1.3 2005/08/05 22:35:10 swildner Exp $
39.\"
40.Dd June 4, 1993
41.Dt STRTOL 3
42.Os
43.Sh NAME
44.Nm strtol ,
45.Nm strtoll ,
46.Nm strtoq
47.Nd "convert a string value to a long, long long, or quad_t integer"
48.Sh LIBRARY
49.Lb libc
50.Sh SYNOPSIS
51.In stdlib.h
52.In limits.h
53.Ft long
54.Fn strtol "const char *nptr" "char **endptr" "int base"
55.Ft long long
56.Fn strtoll "const char *nptr" "char **endptr" "int base"
57.In sys/types.h
58.In stdlib.h
59.In limits.h
60.Ft quad_t
61.Fn strtoq "const char *nptr" "char **endptr" "int base"
62.Sh DESCRIPTION
63The
64.Fn strtol
65function
66converts the string in
67.Fa nptr
68to a
69.Em long
70value.
71The
72.Fn strtoll
73function
74converts the string in
75.Fa nptr
76to a
77.Em long long
78value.
79The
80.Fn strtoq
81function
82converts the string in
83.Fa nptr
84to a
85.Em quad_t
86value.
87The conversion is done according to the given
88.Fa base ,
89which must be between 2 and 36 inclusive,
90or be the special value 0.
91.Pp
92The string may begin with an arbitrary amount of white space
93(as determined by
94.Xr isspace 3 )
95followed by a single optional
96.Ql +
97or
98.Ql -
99sign.
100If
101.Fa base
102is zero or 16,
103the string may then include a
104.Ql 0x
105prefix,
106and the number will be read in base 16; otherwise, a zero
107.Fa base
108is taken as 10 (decimal) unless the next character is
109.Ql 0 ,
110in which case it is taken as 8 (octal).
111.Pp
112The remainder of the string is converted to a
113.Em long
114value in the obvious manner,
115stopping at the first character which is not a valid digit
116in the given base.
117(In bases above 10, the letter
118.Ql A
119in either upper or lower case
120represents 10,
121.Ql B
122represents 11, and so forth, with
123.Ql Z
124representing 35.)
125.Pp
126If
127.Fa endptr
128is non nil,
129.Fn strtol
130stores the address of the first invalid character in
131.Fa *endptr .
132If there were no digits at all, however,
133.Fn strtol
134stores the original value of
135.Fa nptr
136in
137.Fa *endptr .
138(Thus, if
139.Fa *nptr
140is not
141.Ql \e0
142but
143.Fa **endptr
144is
145.Ql \e0
146on return, the entire string was valid.)
147.Sh RETURN VALUES
148The
149.Fn strtol
150function
151returns the result of the conversion,
152unless the value would underflow or overflow.
153If an underflow occurs,
154.Fn strtol
155returns
156.Dv LONG_MIN .
157If an overflow occurs,
158.Fn strtol
159returns
160.Dv LONG_MAX .
161The
162.Fn strtoll
163function
164returns the result of the conversion,
165unless the value would underflow or overflow.
166If an underflow occurs,
167.Fn strtoll
168returns
169.Dv LLONG_MIN .
170If an overflow occurs,
171.Fn strtoll
172returns
173.Dv LLONG_MAX .
174In all cases,
175.Va errno
176is set to
177.Er ERANGE .
178.Sh ERRORS
179.Bl -tag -width Er
180.It Bq Er ERANGE
181The given string was out of range; the value converted has been clamped.
182.El
183.Sh SEE ALSO
184.Xr atof 3 ,
185.Xr atoi 3 ,
186.Xr atol 3 ,
187.Xr strtod 3 ,
188.Xr strtoul 3
189.Sh STANDARDS
190The
191.Fn strtol
192function
193conforms to
194.St -isoC .
195The
196.Fn strtoll
197function
198conforms to
199.St -isoC-99 .
200The
201.Bx
202.Fn strtoq
203function is deprecated.
204.Sh BUGS
205Ignores the current locale.
206