stdlib/strtol.3

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  36 .\"     @(#)strtol.3    8.1 (Berkeley) 6/4/93
  37 .\" $FreeBSD: src/lib/libc/stdlib/strtol.3,v 1.14 2001/09/11 09:39:23 ru Exp $
  38 .\"
  39 .Dd June 4, 1993
  40 .Dt STRTOL 3
  41 .Os
  42 .Sh NAME
  43 .Nm strtol , strtoll , strtoq
  44 .Nd "convert a string value to a long, long long, or quad_t integer"
  45 .Sh LIBRARY
  46 .Lb libc
  47 .Sh SYNOPSIS
  48 .In stdlib.h
  49 .In limits.h
  50 .Ft long
  51 .Fn strtol "const char *nptr" "char **endptr" "int base"
  52 .Ft long long
  53 .Fn strtoll "const char *nptr" "char **endptr" "int base"
  54 .In sys/types.h
  55 .In stdlib.h
  56 .In limits.h
  57 .Ft quad_t
  58 .Fn strtoq "const char *nptr" "char **endptr" "int base"
  59 .Sh DESCRIPTION
  60 The
  61 .Fn strtol
  62 function
  63 converts the string in
  64 .Fa nptr
  65 to a
  66 .Em long
  67 value.
  68 The
  69 .Fn strtoll
  70 function
  71 converts the string in
  72 .Fa nptr
  73 to a
  74 .Em long long
  75 value.
  76 The
  77 .Fn strtoq
  78 function
  79 converts the string in
  80 .Fa nptr
  81 to a
  82 .Em 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 a
 110 .Em long
 111 value in the obvious manner,
 112 stopping at the first character which is not a valid digit
 113 in the given base.
 114 (In bases above 10, the letter
 115 .Ql A
 116 in either upper or lower case
 117 represents 10,
 118 .Ql B
 119 represents 11, and so forth, with
 120 .Ql Z
 121 representing 35.)
 122 .Pp
 123 If
 124 .Fa endptr
 125 is non nil,
 126 .Fn strtol
 127 stores the address of the first invalid character in
 128 .Fa *endptr .
 129 If there were no digits at all, however,
 130 .Fn strtol
 131 stores the original value of
 132 .Fa nptr
 133 in
 134 .Fa *endptr .
 135 (Thus, if
 136 .Fa *nptr
 137 is not
 138 .Ql \e0
 139 but
 140 .Fa **endptr
 141 is
 142 .Ql \e0
 143 on return, the entire string was valid.)
 144 .Sh RETURN VALUES
 145 The
 146 .Fn strtol
 147 or
 148 .Fn strtoll
 149 function
 150 returns the result of the conversion,
 151 unless the value would underflow or overflow.
 152 If no conversion could be performed, 0 is returned and
 153 the global variable
 154 .Va errno
 155 is set to
 156 .Er EINVAL .
 157 If an underflow occurs,
 158 .Fn strtol
 159 returns
 160 .Dv LONG_MIN .
 161 If an overflow occurs,
 162 .Fn strtol
 163 returns
 164 .Dv LONG_MAX .
 165 If an underflow occurs,
 166 .Fn strtoll
 167 returns
 168 .Dv LLONG_MIN .
 169 If an overflow occurs,
 170 .Fn strtoll
 171 returns
 172 .Dv LLONG_MAX .
 173 In all cases,
 174 .Va errno
 175 is set to
 176 .Er ERANGE .
 177 .Sh ERRORS
 178 .Bl -tag -width Er
 179 .It Bq Er EINVAL
 180 The value of
 181 .Fa base
 182 is not supported or
 183 no conversion could be performed.
 184 .It Bq Er ERANGE
 185 The given string was out of range; the value converted has been clamped.
 186 .El
 187 .Sh SEE ALSO
 188 .Xr atof 3 ,
 189 .Xr atoi 3 ,
 190 .Xr atol 3 ,
 191 .Xr strtod 3 ,
 192 .Xr strtoul 3
 193 .Sh STANDARDS
 194 The
 195 .Fn strtol
 196 function
 197 conforms to
 198 .St -isoC .
 199 The
 200 .Fn strtoll
 201 function
 202 conforms to
 203 .St -isoC-99 .
 204 The
 205 .Bx
 206 .Fn strtoq
 207 function is deprecated.