stdlib/strtoul.3

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  36 .\"     @(#)strtoul.3   8.1 (Berkeley) 6/4/93
  37 .\" $FreeBSD: src/lib/libc/stdlib/strtoul.3,v 1.14 2001/09/11 09:39:23 ru Exp $
  38 .\"
  39 .Dd June 4, 1993
  40 .Dt STRTOUL 3
  41 .Os
  42 .Sh NAME
  43 .Nm strtoul , strtoull , strtouq
  44 .Nd "convert a string to an unsigned long, unsigned long long, or uquad_t integer"
  45 .Sh LIBRARY
  46 .Lb libc
  47 .Sh SYNOPSIS
  48 .In stdlib.h
  49 .In limits.h
  50 .Ft unsigned long
  51 .Fn strtoul "const char *nptr" "char **endptr" "int base"
  52 .Ft unsigned long long
  53 .Fn strtoull "const char *nptr" "char **endptr" "int base"
  54 .In sys/types.h
  55 .In stdlib.h
  56 .In limits.h
  57 .Ft u_quad_t
  58 .Fn strtouq "const char *nptr" "char **endptr" "int base"
  59 .Sh DESCRIPTION
  60 The
  61 .Fn strtoul
  62 function
  63 converts the string in
  64 .Fa nptr
  65 to an
  66 .Em unsigned long
  67 value.
  68 The
  69 .Fn strtoull
  70 function
  71 converts the string in
  72 .Fa nptr
  73 to an
  74 .Em unsigned long long
  75 value.
  76 The
  77 .Fn strtouq
  78 function
  79 converts the string in
  80 .Fa nptr
  81 to a
  82 .Em u_quad_t
  83 value.
  84 The conversion is done according to the given
  85 .Fa base ,
  86 which must be between 2 and 36 inclusive,
  87 or be the special value 0.
  88 .Pp
  89 The string may begin with an arbitrary amount of white space
  90 (as determined by
  91 .Xr isspace 3 )
  92 followed by a single optional
  93 .Ql +
  94 or
  95 .Ql -
  96 sign.
  97 If
  98 .Fa base
  99 is zero or 16,
 100 the string may then include a
 101 .Ql 0x
 102 prefix,
 103 and the number will be read in base 16; otherwise, a zero
 104 .Fa base
 105 is taken as 10 (decimal) unless the next character is
 106 .Ql 0 ,
 107 in which case it is taken as 8 (octal).
 108 .Pp
 109 The remainder of the string is converted to an
 110 .Em unsigned long
 111 value in the obvious manner,
 112 stopping at the end of the string
 113 or at the first character that does not produce a valid digit
 114 in the given base.
 115 (In bases above 10, the letter
 116 .Ql A
 117 in either upper or lower case
 118 represents 10,
 119 .Ql B
 120 represents 11, and so forth, with
 121 .Ql Z
 122 representing 35.)
 123 .Pp
 124 If
 125 .Fa endptr
 126 is non nil,
 127 .Fn strtoul
 128 stores the address of the first invalid character in
 129 .Fa *endptr .
 130 If there were no digits at all, however,
 131 .Fn strtoul
 132 stores the original value of
 133 .Fa nptr
 134 in
 135 .Fa *endptr .
 136 (Thus, if
 137 .Fa *nptr
 138 is not
 139 .Ql \e0
 140 but
 141 .Fa **endptr
 142 is
 143 .Ql \e0
 144 on return, the entire string was valid.)
 145 .Sh RETURN VALUES
 146 The
 147 .Fn strtoul
 148 or
 149 .Fn strtoull
 150 function
 151 returns either the result of the conversion
 152 or, if there was a leading minus sign,
 153 the negation of the result of the conversion,
 154 unless the original (non-negated) value would overflow;
 155 in the latter case,
 156 .Fn strtoul
 157 returns
 158 .Dv ULONG_MAX
 159 and
 160 .Fn strtoull
 161 returns
 162 .Dv ULLONG_MAX .
 163 In all cases,
 164 .Va errno
 165 is set to
 166 .Er ERANGE .
 167 If no conversion could be performed, 0 is returned and
 168 the global variable
 169 .Va errno
 170 is set to
 171 .Er EINVAL .
 172 .Sh ERRORS
 173 .Bl -tag -width Er
 174 .It Bq Er EINVAL
 175 The value of
 176 .Fa base
 177 is not supported or
 178 no conversion could be performed.
 179 .It Bq Er ERANGE
 180 The given string was out of range; the value converted has been clamped.
 181 .El
 182 .Sh SEE ALSO
 183 .Xr strtol 3
 184 .Sh STANDARDS
 185 The
 186 .Fn strtoul
 187 function
 188 conforms to
 189 .St -isoC .
 190 The
 191 .Fn strtoull
 192 function
 193 conforms to
 194 .St -isoC-99 .
 195 The
 196 .Bx
 197 .Fn strtoq
 198 function is deprecated.