xref: /dragonfly/lib/libc/stdlib/strtol.3 (revision c3762235)
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32.\"     @(#)strtol.3	8.1 (Berkeley) 6/4/93
33.\" $FreeBSD: src/lib/libc/stdlib/strtol.3,v 1.23 2007/04/10 11:17:00 ru Exp $
34.\"
35.Dd December 25, 2013
36.Dt STRTOL 3
37.Os
38.Sh NAME
39.Nm strtol ,
40.Nm strtol_l ,
41.Nm strtoll ,
42.Nm strtoll_l ,
43.Nm strtoimax ,
44.Nm strtoimax_l ,
45.Nm strtoq
46.Nd "convert a string value to a"
47.Vt long , "long long" , intmax_t
48or
49.Vt quad_t
50integer
51.Sh LIBRARY
52.Lb libc
53.Sh SYNOPSIS
54.In stdlib.h
55.In limits.h
56.Ft long
57.Fn strtol "const char * restrict nptr" "char ** restrict endptr" "int base"
58.Ft long long
59.Fn strtoll "const char * restrict nptr" "char ** restrict endptr" "int base"
60.In inttypes.h
61.Ft intmax_t
62.Fn strtoimax "const char * restrict nptr" "char ** restrict endptr" "int base"
63.In sys/types.h
64.Ft quad_t
65.Fn strtoq "const char *nptr" "char **endptr" "int base"
66.In xlocale.h
67.Ft long
68.Fn strtol_l "const char * restrict nptr" "char ** restrict endptr" "int base" "locale_t locale"
69.Ft long long
70.Fn strtoll_l "const char * restrict nptr" "char ** restrict endptr" "int base" "locale_t locale"
71.Ft intmax_t
72.Fn strtoimax_l "const char * restrict nptr" "char ** restrict endptr" "int base" "locale_t locale"
73.Sh DESCRIPTION
74The
75.Fn strtol
76and
77.Fn strtol_l
78functions convert the string in
79.Fa nptr
80to a
81.Vt long
82value.
83The
84.Fn strtoll
85and
86.Fn strtoll_l
87functions convert the string in
88.Fa nptr
89to a
90.Vt "long long"
91value.
92The
93.Fn strtoimax
94and
95.Fn strtoimax_l
96functions convert the string in
97.Fa nptr
98to an
99.Vt intmax_t
100value.
101The
102.Fn strtoq
103function
104converts the string in
105.Fa nptr
106to a
107.Vt quad_t
108value.
109The conversion is done according to the given
110.Fa base ,
111which must be between 2 and 36 inclusive,
112or be the special value 0.
113.Pp
114The string may begin with an arbitrary amount of white space
115(as determined by
116.Xr isspace 3
117or
118.Xr isspace_l 3 )
119followed by a single optional
120.Ql +
121or
122.Ql -
123sign.
124If
125.Fa base
126is zero or 16,
127the string may then include a
128.Dq Li 0x
129prefix,
130and the number will be read in base 16; otherwise, a zero
131.Fa base
132is taken as 10 (decimal) unless the next character is
133.Ql 0 ,
134in which case it is taken as 8 (octal).
135.Pp
136The remainder of the string is converted to a
137.Vt long , "long long" , intmax_t
138or
139.Vt quad_t
140value in the obvious manner,
141stopping at the first character which is not a valid digit
142in the given base.
143(In bases above 10, the letter
144.Ql A
145in either upper or lower case
146represents 10,
147.Ql B
148represents 11, and so forth, with
149.Ql Z
150representing 35.)
151.Pp
152If
153.Fa endptr
154is not
155.Dv NULL ,
156.Fn strtol
157and
158.Fn strtol_l
159store the address of the first invalid character in
160.Fa *endptr .
161If there were no digits at all, however,
162.Fn strtol
163and
164.Fn strtol_l
165store the original value of
166.Fa nptr
167in
168.Fa *endptr .
169(Thus, if
170.Fa *nptr
171is not
172.Ql \e0
173but
174.Fa **endptr
175is
176.Ql \e0
177on return, the entire string was valid.)
178.Pp
179The
180.Fn strtol_l ,
181.Fn strtoll_l ,
182and
183.Fn strtoimax_l
184functions take an explicit
185.Fa locale
186argument, whereas the
187.Fn strtol ,
188.Fn strtoll ,
189.Fn strtoimax ,
190and
191.Fn strtoq
192functions use the current global or per-thread locale.
193.Sh RETURN VALUES
194The
195.Fn strtol ,
196.Fn strtol_l ,
197.Fn strtoll ,
198.Fn strtoll_l ,
199.Fn strtoimax ,
200.Fn strtoimax_l ,
201and
202.Fn strtoq
203functions
204return the result of the conversion,
205unless the value would underflow or overflow.
206If no conversion could be performed, 0 is returned and
207the global variable
208.Va errno
209is set to
210.Er EINVAL
211(the last feature is not portable across all platforms).
212If an overflow or underflow occurs,
213.Va errno
214is set to
215.Er ERANGE
216and the function return value is clamped according
217to the following table.
218.Bl -column -offset indent ".Fn strtoimax_l" ".Sy underflow" ".Sy overflow"
219.It Sy Function Ta Sy underflow Ta Sy overflow
220.It Fn strtol Ta Dv LONG_MIN Ta Dv LONG_MAX
221.It Fn strtol_l Ta Dv LONG_MIN Ta Dv LONG_MAX
222.It Fn strtoll Ta Dv LLONG_MIN Ta Dv LLONG_MAX
223.It Fn strtoll_l Ta Dv LLONG_MIN Ta Dv LLONG_MAX
224.It Fn strtoimax Ta Dv INTMAX_MIN Ta Dv INTMAX_MAX
225.It Fn strtoimax_l Ta Dv INTMAX_MIN Ta Dv INTMAX_MAX
226.It Fn strtoq Ta Dv LLONG_MIN Ta Dv LLONG_MAX
227.El
228.Sh ERRORS
229.Bl -tag -width Er
230.It Bq Er EINVAL
231The value of
232.Fa base
233is not supported or
234no conversion could be performed
235(the last feature is not portable across all platforms).
236.It Bq Er ERANGE
237The given string was out of range; the value converted has been clamped.
238.El
239.Sh SEE ALSO
240.Xr atof 3 ,
241.Xr atoi 3 ,
242.Xr atol 3 ,
243.Xr strtod 3 ,
244.Xr strtonum 3 ,
245.Xr strtoul 3 ,
246.Xr wcstol 3 ,
247.Xr xlocale 3
248.Sh STANDARDS
249The
250.Fn strtol
251function
252conforms to
253.St -isoC .
254The
255.Fn strtoll
256and
257.Fn strtoimax
258functions
259conform to
260.St -isoC-99 .
261The
262.Bx
263.Fn strtoq
264-function is deprecated.
265