[unix-history] / usr / src / lib / libc / stdlib / strtoul.3

.\" Copyright (c) 1990 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek.
.\"
.\" %sccs.include.redist.man%
.\"
.\"	@(#)strtoul.3	5.1 (Berkeley) %G%
.\"
.TH STRTOUL 3 ""
.UC 7
.SH NAME
strtoul \- convert a string to an unsigned long integer
.SH SYNOPSIS
.B #include <stdlib.h>
.br
.B #include <limits.h>
.PP
.B "unsigned long strtoul(char *nptr, char **endptr, int base);
.SH DESCRIPTION
.B Strtoul
converts the string in
.I nptr
to an
.B "unsigned long"
value according to the given
.IR base ,
which must be between 2 and 36 inclusive,
or be the special value 0.
.PP
The string may begin with an arbitrary amount of white space
(as determined by
.BR isspace ;
see
.IR ctype (3)),
followed by a single optional `+' or `-' sign.
If
.I base
is zero or 16,
the string may then include a `0x' prefix,
and the number will be read in base 16; otherwise, a zero
.I base
is taken as 10 (decimal) unless the next character is `0',
in which case it is taken as 8 (octal).
.PP
The remainder of the string is converted to an
.B "unsigned long"
value in the obvious manner,
stopping at the end of the string
or at the first character that does not produce a valid digit
in the given base.
(In bases above 10, the letter `A' in either upper or lower case
represents 10, `B' represents 11, and so forth, with `Z' representing 35.)
.PP
If
.I endptr
is non nil,
.B strtoul
stores the address of the first invalid character in
.IR *endptr .
If there were no digits at all, however,
.B strtoul
stores the original value of
.I nptr
in
.IR *endptr .
(Thus, if
.I *nptr
is not '\e0' but
.IR **endptr
is '\e0' on return, the entire string was valid.)
.SH RETURN VALUE
.B Strtoul
returns either the result of the conversion
or, if there was a leading minus sign,
the negation of the result of the conversion,
unless the original (non-negated) value would overflow;
in the latter case,
.B strtoul
returns
.B ULONG_MAX
and sets
.B errno
to
.BR ERANGE .
.SH ERRORS
.TP
[ERANGE]
The given string was out of range; the value converted has been clamped.
.SH SEE ALSO
strtol(3)
.SH STANDARDS
.B Strtoul
conforms to ANSI X3.159-1989 (``ANSI C'').
.SH BUGS
Ignores the current locale.
Commit	Line	Data
375c4de4 KB	1	.\" Copyright (c) 1990 The Regents of the University of California.
	2	.\" All rights reserved.
	3	.\"
	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" Chris Torek.
	6	.\"
	7	.\" %sccs.include.redist.man%
	8	.\"
	9	.\" @(#)strtoul.3 5.1 (Berkeley) %G%
	10	.\"
	11	.TH STRTOUL 3 ""
	12	.UC 7
	13	.SH NAME
	14	strtoul \- convert a string to an unsigned long integer
	15	.SH SYNOPSIS
	16	.B #include <stdlib.h>
	17	.br
	18	.B #include <limits.h>
	19	.PP
	20	.B "unsigned long strtoul(char nptr, char *endptr, int base);
	21	.SH DESCRIPTION
	22	.B Strtoul
	23	converts the string in
	24	.I nptr
	25	to an
	26	.B "unsigned long"
	27	value according to the given
	28	.IR base ,
	29	which must be between 2 and 36 inclusive,
	30	or be the special value 0.
	31	.PP
	32	The string may begin with an arbitrary amount of white space
	33	(as determined by
	34	.BR isspace ;
	35	see
	36	.IR ctype (3)),
	37	followed by a single optional `+' or `-' sign.
	38	If
	39	.I base
	40	is zero or 16,
	41	the string may then include a `0x' prefix,
	42	and the number will be read in base 16; otherwise, a zero
	43	.I base
	44	is taken as 10 (decimal) unless the next character is `0',
	45	in which case it is taken as 8 (octal).
	46	.PP
	47	The remainder of the string is converted to an
	48	.B "unsigned long"
	49	value in the obvious manner,
	50	stopping at the end of the string
	51	or at the first character that does not produce a valid digit
	52	in the given base.
	53	(In bases above 10, the letter `A' in either upper or lower case
	54	represents 10, `B' represents 11, and so forth, with `Z' representing 35.)
	55	.PP
	56	If
	57	.I endptr
	58	is non nil,
	59	.B strtoul
	60	stores the address of the first invalid character in
	61	.IR *endptr .
	62	If there were no digits at all, however,
	63	.B strtoul
	64	stores the original value of
65	.I nptr
66	in
67	.IR *endptr .
68	(Thus, if
69	.I *nptr
70	is not '\e0' but
71	.IR **endptr
72	is '\e0' on return, the entire string was valid.)
73	.SH RETURN VALUE
74	.B Strtoul
75	returns either the result of the conversion
76	or, if there was a leading minus sign,
77	the negation of the result of the conversion,
78	unless the original (non-negated) value would overflow;
79	in the latter case,
80	.B strtoul
81	returns
82	.B ULONG_MAX
83	and sets
84	.B errno
85	to
86	.BR ERANGE .
87	.SH ERRORS
88	.TP
89	[ERANGE]
90	The given string was out of range; the value converted has been clamped.
91	.SH SEE ALSO
92	strtol(3)
93	.SH STANDARDS
94	.B Strtoul
95	conforms to ANSI X3.159-1989 (``ANSI C'').
96	.SH BUGS
97	Ignores the current locale.