1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
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8 .\" Permission is granted to copy and distribute modified versions of this
9 .\" manual under the conditions for verbatim copying, provided that the
10 .\" entire resulting derived work is distributed under the terms of a
11 .\" permission notice identical to this one.
13 .\" Since the Linux kernel and libraries are constantly changing, this
14 .\" manual page may be incorrect or out-of-date. The author(s) assume no
15 .\" responsibility for errors or omissions, or for damages resulting from
16 .\" the use of the information contained herein. The author(s) may not
17 .\" have taken the same level of care in the production of this manual,
18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
29 .\" Modified Sun Jul 25 10:54:03 1993 by Rik Faith (faith@cs.unc.edu)
30 .\" Fixed typo, aeb, 950823
31 .\" 2002-02-22, joey, mihtjel: Added strtoull()
33 .TH STRTOUL 3 2017-09-15 "GNU" "Linux Programmer's Manual"
35 strtoul, strtoull, strtouq \- convert a string to an unsigned long integer
38 .B #include <stdlib.h>
40 .BI "unsigned long int strtoul(const char *" nptr ", char **" endptr \
43 .BI "unsigned long long int strtoull(const char *" nptr ", char **" endptr ,
48 Feature Test Macro Requirements for glibc (see
49 .BR feature_test_macros (7)):
56 || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
62 function converts the initial part of the string
66 .I "unsigned long int"
67 value according to the
70 which must be between 2 and 36 inclusive, or be
73 The string may begin with an arbitrary amount of white space (as
76 followed by a single optional \(aq+\(aq or \(aq\-\(aq
80 is zero or 16, the string may then include a
81 "0x" prefix, and the number will be read in base 16; otherwise, a
84 is taken as 10 (decimal) unless the next character
85 is \(aq0\(aq, in which case it is taken as 8 (octal).
87 The remainder of the string is converted to an
88 .I "unsigned long int"
89 value in the obvious manner,
90 stopping at the first character which is not a
91 valid digit in the given base.
92 (In bases above 10, the letter \(aqA\(aq in
93 either uppercase or lowercase represents 10, \(aqB\(aq represents 11, and so
94 forth, with \(aqZ\(aq representing 35.)
100 stores the address of the
101 first invalid character in
103 If there were no digits at
106 stores the original value of
113 is not \(aq\\0\(aq but
115 is \(aq\\0\(aq on return, the entire string is valid.
119 function works just like the
121 function but returns an
122 .I "unsigned long long int"
127 function returns either the result of the conversion
128 or, if there was a leading minus sign, the negation of the result of the
129 conversion represented as an unsigned value,
130 unless the original (nonnegated) value would overflow; in
139 Precisely the same holds for
151 contains an unsupported value.
154 The resulting value was out of range.
156 The implementation may also set
161 no conversion was performed (no digits seen, and 0 returned).
163 For an explanation of the terms used in this section, see
169 Interface Attribute Value
174 T} Thread safety MT-Safe locale
178 POSIX.1-2001, POSIX.1-2008, C89, C99 SVr4.
181 POSIX.1-2001, POSIX.1-2008, C99.
185 can legitimately return 0 or
190 on both success and failure, the calling program should set
192 to 0 before the call,
193 and then determine if an error occurred by checking whether
195 has a nonzero value after the call.
197 In locales other than the "C" locale, other strings may be accepted.
198 (For example, the thousands separator of the current locale may be
205 .BI "u_quad_t strtouq(const char *" nptr ", char **" endptr ", int " base );
209 with completely analogous definition.
210 Depending on the wordsize of the current architecture, this
216 Negative values are considered valid input and are
217 silently converted to the equivalent
218 .I "unsigned long int"
221 See the example on the
224 the use of the functions described in this manual page is similar.