xref: /netbsd/lib/libc/stdlib/strtoul.3 (revision bf9ec67e)
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38.\"     from: @(#)strtoul.3	8.1 (Berkeley) 6/4/93
39.\"
40.Dd April 26, 2001
41.Dt STRTOUL 3
42.Os
43.Sh NAME
44.Nm strtoul ,
45.Nm strtoull ,
46.Nm strtoumax ,
47.Nm strtouq
48.Nd "convert a string to an unsigned long, unsigned long long, uintmax_t or uquad_t integer"
49.Sh LIBRARY
50.Lb libc
51.Sh SYNOPSIS
52.Fd #include \*[Lt]stdlib.h\*[Gt]
53.Fd #include \*[Lt]limits.h\*[Gt]
54.Ft unsigned long int
55.Fn strtoul "const char * restrict nptr" "char ** restrict endptr" "int base"
56.Ft unsigned long long int
57.Fn strtoull "const char * restrict nptr" "char ** restrict endptr" "int base"
58.Pp
59.Fd #include \*[Lt]inttypes.h\*[Gt]
60.Ft uintmax_t
61.Fn strtoumax "const char * restrict nptr" "char ** restrict endptr" "int base"
62.Pp
63.Fd #include \*[Lt]sys/types.h\*[Gt]
64.Fd #include \*[Lt]stdlib.h\*[Gt]
65.Fd #include \*[Lt]limits.h\*[Gt]
66.Ft u_quad_t
67.Fn strtouq "const char * restrict nptr" "char ** restrict endptr" "int base"
68.Sh DESCRIPTION
69The
70.Fn strtoul
71function
72converts the string in
73.Fa nptr
74to an
75.Em unsigned long int
76value.
77The
78.Fn strtoull
79function
80converts the string in
81.Fa nptr
82to an
83.Em unsigned long long int
84value.
85The
86.Fn strtoumax
87function
88converts the string in
89.Fa nptr
90to an
91.Em uintmax_t
92value.
93The
94.Fn strtouq
95function
96converts the string in
97.Fa nptr
98to a
99.Em u_quad_t
100value.
101The conversion is done according to the given
102.Fa base ,
103which must be between 2 and 36 inclusive,
104or be the special value 0.
105.Pp
106The string may begin with an arbitrary amount of white space
107(as determined by
108.Xr isspace 3 )
109followed by a single optional
110.Ql +
111or
112.Ql -
113sign.
114If
115.Fa base
116is zero or 16,
117the string may then include a
118.Ql 0x
119prefix,
120and the number will be read in base 16; otherwise, a zero
121.Fa base
122is taken as 10 (decimal) unless the next character is
123.Ql 0 ,
124in which case it is taken as 8 (octal).
125.Pp
126The remainder of the string is converted to an
127.Em unsigned long
128value in the obvious manner,
129stopping at the end of the string
130or at the first character that does not produce a valid digit
131in the given base.
132(In bases above 10, the letter
133.Ql A
134in either upper or lower case
135represents 10,
136.Ql B
137represents 11, and so forth, with
138.Ql Z
139representing 35.)
140.Pp
141If
142.Fa endptr
143is non nil,
144.Fn strtoul
145stores the address of the first invalid character in
146.Fa *endptr .
147If there were no digits at all, however,
148.Fn strtoul
149stores the original value of
150.Fa nptr
151in
152.Fa *endptr .
153(Thus, if
154.Fa *nptr
155is not
156.Ql \e0
157but
158.Fa **endptr
159is
160.Ql \e0
161on return, the entire string was valid.)
162.Sh RETURN VALUES
163The
164.Fn strtoul
165function
166returns either the result of the conversion
167or, if there was a leading minus sign,
168the negation of the result of the conversion,
169unless the original (non-negated) value would overflow;
170in the latter case,
171.Fn strtoul
172returns
173.Dv ULONG_MAX ,
174.Fn strtoull
175returns
176.Dv ULLONG_MAX ,
177.Fn strtoumax
178returns
179.Dv UINTMAX_MAX ,
180and the global variable
181.Va errno
182is set to
183.Er ERANGE .
184.Sh ERRORS
185.Bl -tag -width Er
186.It Bq Er ERANGE
187The given string was out of range; the value converted has been clamped.
188.El
189.Sh SEE ALSO
190.Xr strtoimax 3 ,
191.Xr strtol 3 ,
192.Xr strtoll 3
193.Sh STANDARDS
194The
195.Fn strtoul
196function
197conforms to
198.St -ansiC .
199The
200.Fn strtoull
201and
202.Fn strtoumax
203functions conform to
204.St -isoC99 .
205.Sh BUGS
206Ignores the current locale.
207