getconf.tproj/getconf.1

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  31 .Dd September 18, 2002
  32 .Dt GETCONF 1
  33 .Os
  34 .Sh NAME
  35 .Nm getconf
  36 .Nd retrieve standard configuration variables
  37 .Sh SYNOPSIS
  38 .Nm
  39 .Op Fl v Ar environment
  40 .Ar path_var
  41 .Ar file
  42 .Nm
  43 .Op Fl v Ar environment
  44 .Ar system_var
  45 .Sh DESCRIPTION
  46 The
  47 .Nm
  48 utility prints the value of a
  49 .Tn POSIX
  50 or
  51 .Tn X/Open
  52 path or system configuration variable to the standard output.
  53 If the specified variable is undefined, the string
  54 .Dq Li undefined
  55 is output.
  56 .Pp
  57 The first form of the command, with two mandatory
  58 arguments, retrieves file- and file system-specific
  59 configuration variables using
  60 .Xr pathconf 2 .
  61 The second form, with a single argument, retrieves system
  62 configuration variables using
  63 .Xr confstr 3
  64 and
  65 .Xr sysconf 3 ,
  66 depending on the type of variable.
  67 As an extension, the second form can also be used to query static limits from
  68 .In limits.h .
  69 .Pp
  70 All
  71 .Xr sysconf 3
  72 and
  73 .Xr pathconf 2
  74 variables use the same name as the manifest constants defined in
  75 the relevant standard C-language bindings, including any leading
  76 underscore or prefix.
  77 That is to say,
  78 .Ar system_var
  79 might be
  80 .Dv ARG_MAX
  81 or
  82 .Dv _POSIX_VERSION ,
  83 as opposed to the
  84 .Xr sysconf 3
  85 names
  86 .Dv _SC_ARG_MAX
  87 or
  88 .Dv _SC_POSIX_VERSION .
  89 Variables retrieved from
  90 .Xr confstr 3
  91 have the leading
  92 .Ql _CS_
  93 stripped off; thus,
  94 .Dv _CS_PATH
  95 is queried by a
  96 .Ar system_var
  97 of
  98 .Dq Li PATH .
  99 .Ss Programming Environments
 100 The
 101 .Fl v Ar environment
 102 option specifies a
 103 .St -p1003.1-2001
 104 programming environment under which the values are to be queried.
 105 This option currently does nothing, but may in the future be used
 106 to select between 32-bit and 64-bit execution environments on platforms
 107 which support both.
 108 Specifying an environment which is not supported on the current execution
 109 platform gives undefined results.
 110 .Pp
 111 The standard programming environments are as follows:
 112 .Bl -tag -width ".Li POSIX_V6_LPBIG_OFFBIG" -offset indent
 113 .It Li POSIX_V6_ILP32_OFF32
 114 Exactly 32-bit integer, long, pointer, and file offset.
 115 .Sy Supported platforms :
 116 None.
 117 .It Li POSIX_V6_ILP32_OFFBIG
 118 Exactly 32-bit integer, long, and pointer; at least 64-bit file offset.
 119 .Sy Supported platforms :
 120 .Tn IA32 ,
 121 .Tn PowerPC .
 122 .It Li POSIX_V6_LP64_OFF64
 123 Exactly 32-bit integer; exactly 64-bit long, pointer, and file offset.
 124 .Sy Supported platforms :
 125 .Tn Alpha ,
 126 .Tn SPARC64 .
 127 .It Li POSIX_V6_LPBIG_OFFBIG
 128 At least 32-bit integer; at least 64-bit long, pointer, and file offset.
 129 .Sy Supported platforms :
 130 None.
 131 .El
 132 .Pp
 133 The command:
 134 .Pp
 135 .Dl "getconf POSIX_V6_WIDTH_RESTRICTED_ENVS"
 136 .Pp
 137 returns a newline-separated list of environments in which the width
 138 of certain fundamental types is no greater than the width of the native
 139 C type
 140 .Vt long .
 141 At present, all programming environments supported by
 142 .Fx
 143 have this property.
 144 Several of the
 145 .Xr confstr 3
 146 variables provide information on the necessary compiler and linker flags
 147 to use the standard programming environments described above.
 148 .Pp
 149 Many of these values are also available through the
 150 .Xr sysctl 8
 151 mechanism.
 152 .Sh DIAGNOSTICS
 153 .Ex -std
 154 Use of a
 155 .Ar system_var
 156 or
 157 .Ar path_var
 158 which is completely unrecognized is considered an error,
 159 causing a diagnostic message to be written to standard error.
 160 One
 161 which is known but merely undefined does not result in an error
 162 indication.
 163 The
 164 .Nm
 165 utility recognizes all of the variables defined for
 166 .St -p1003.1-2001 ,
 167 including those which are not currently implemented.
 168 .Sh EXAMPLES
 169 The command:
 170 .Pp
 171 .Dl "getconf PATH"
 172 .Pp
 173 will display the system default setting for the
 174 .Ev PATH
 175 environment variable.
 176 .Pp
 177 The command:
 178 .Pp
 179 .Dl "getconf NAME_MAX /tmp"
 180 .Pp
 181 will display the maximum length of a filename in the
 182 .Pa /tmp
 183 directory.
 184 .Pp
 185 The command:
 186 .Pp
 187 .Dl "getconf -v POSIX_V6_LPBIG_OFFBIG LONG_MAX"
 188 .Pp
 189 will display the maximum value of the C type
 190 .Vt long
 191 in the
 192 .Li POSIX_V6_LPBIG_OFFBIG
 193 programming environment,
 194 if the system supports that environment.
 195 .Sh SEE ALSO
 196 .Xr pathconf 2 ,
 197 .Xr confstr 3 ,
 198 .Xr sysconf 3 ,
 199 .Xr sysctl 8
 200 .Sh STANDARDS
 201 The
 202 .Nm
 203 utility is expected to be compliant with
 204 .St -p1003.1-2001 .
 205 .Sh HISTORY
 206 The
 207 .Nm
 208 utility first appeared in
 209 .Fx 5.0 .
 210 .Sh AUTHORS
 211 .An Garrett A. Wollman Aq wollman@lcs.mit.edu