code.delx.au - gnu-emacs/blob - doc/lispref/errors.texi

   1 @c -*-texinfo-*-
   2 @c This is part of the GNU Emacs Lisp Reference Manual.
   3 @c Copyright (C) 1990-1993, 1999, 2001-2012 Free Software Foundation, Inc.
   4 @c See the file elisp.texi for copying conditions.
   5 @setfilename ../../info/errors
   6 @node Standard Errors, Standard Keymaps, GNU Emacs Internals, Top
   7 @appendix Standard Errors
   8 @cindex standard errors
   9
  10   Here is a list of the more important error symbols in standard Emacs,
  11 grouped by concept.  The list includes each symbol's message (on the
  12 @code{error-message} property of the symbol) and a cross reference to a
  13 description of how the error can occur.
  14
  15   Each error symbol has an @code{error-conditions} property that is a
  16 list of symbols.  Normally this list includes the error symbol itself
  17 and the symbol @code{error}.  Occasionally it includes additional
  18 symbols, which are intermediate classifications, narrower than
  19 @code{error} but broader than a single error symbol.  For example, all
  20 the errors in accessing files have the condition @code{file-error}.  If
  21 we do not say here that a certain error symbol has additional error
  22 conditions, that means it has none.
  23
  24   As a special exception, the error symbol @code{quit} does not have the
  25 condition @code{error}, because quitting is not considered an error.
  26
  27 @c You can grep for "(put 'foo 'error-conditions ...) to find
  28 @c examples defined in Lisp.  Eg soap-client.el, sasl.el.
  29   Most of these error symbols are defined in C (mainly @file{data.c}),
  30 but some are defined in Lisp.  For example, the file @file{userlock.el}
  31 defines the @code{file-locked} and @code{file-supersession} errors.
  32 Several of the specialized Lisp libraries distributed with Emacs
  33 define their own error symbols.  We do not attempt to list of all
  34 those here.
  35
  36   @xref{Errors}, for an explanation of how errors are generated and
  37 handled.
  38
  39 @table @code
  40 @item error
  41 @code{"error"}@*
  42 @xref{Errors}.
  43
  44 @item quit
  45 @code{"Quit"}@*
  46 @xref{Quitting}.
  47
  48 @item args-out-of-range
  49 @code{"Args out of range"}@*
  50 This happens when trying to access an element beyond the range of a
  51 sequence or buffer.@*
  52 @xref{Sequences Arrays Vectors}, @xref{Text}.
  53
  54 @item arith-error
  55 @code{"Arithmetic error"}@*
  56 @xref{Arithmetic Operations}.
  57
  58 @item beginning-of-buffer
  59 @code{"Beginning of buffer"}@*
  60 @xref{Character Motion}.
  61
  62 @item buffer-read-only
  63 @code{"Buffer is read-only"}@*
  64 @xref{Read Only Buffers}.
  65
  66 @item circular-list
  67 @code{"List contains a loop"}@*
  68 This happens when some operations (e.g. resolving face names)
  69 encounter circular structures.@*
  70 @xref{Circular Objects}.
  71
  72 @item cl-assertion-failed
  73 @code{"Assertion failed"}@*
  74 This happens when the @code{assert} macro fails a test.@*
  75 @xref{Assertions,,, cl, Common Lisp Extensions}.
  76
  77 @item coding-system-error
  78 @code{"Invalid coding system"}@*
  79 @xref{Lisp and Coding Systems}.
  80
  81 @item cyclic-function-indirection
  82 @code{"Symbol's chain of function indirections contains a loop"}@*
  83 @xref{Function Indirection}.
  84
  85 @item cyclic-variable-indirection
  86 @code{"Symbol's chain of variable indirections contains a loop"}@*
  87 @xref{Variable Aliases}.
  88
  89 @item dbus-error
  90 @code{"D-Bus error"}@*
  91 This is only defined if Emacs was compiled with D-Bus support.@*
  92 @xref{Errors and Events,,, dbus, D-Bus integration in Emacs}.
  93
  94 @item end-of-buffer
  95 @code{"End of buffer"}@*
  96 @xref{Character Motion}.
  97
  98 @item end-of-file
  99 @code{"End of file during parsing"}@*
 100 Note that this is not a subcategory of @code{file-error},
 101 because it pertains to the Lisp reader, not to file I/O.@*
 102 @xref{Input Functions}.
 103
 104 @item file-already-exists
 105 This is a subcategory of @code{file-error}.@*
 106 @xref{Writing to Files}.
 107
 108 @item file-date-error
 109 This is a subcategory of @code{file-error}.  It occurs when
 110 @code{copy-file} tries and fails to set the last-modification time of
 111 the output file.@*
 112 @xref{Changing Files}.
 113
 114 @item file-error
 115 We do not list the error-strings of this error and its subcategories,
 116 because the error message is normally constructed from the data items
 117 alone when the error condition @code{file-error} is present.  Thus,
 118 the error-strings are not very relevant.  However, these error symbols
 119 do have @code{error-message} properties, and if no data is provided,
 120 the @code{error-message} property @emph{is} used.@*
 121 @xref{Files}.
 122
 123 @c jka-compr.el
 124 @item compression-error
 125 This is a subcategory of @code{file-error}, which results from
 126 problems handling a compressed file.@*
 127 @xref{How Programs Do Loading}.
 128
 129 @c userlock.el
 130 @item file-locked
 131 This is a subcategory of @code{file-error}.@*
 132 @xref{File Locks}.
 133
 134 @c userlock.el
 135 @item file-supersession
 136 This is a subcategory of @code{file-error}.@*
 137 @xref{Modification Time}.
 138
 139 @c net/ange-ftp.el
 140 @item ftp-error
 141 This is a subcategory of @code{file-error}, which results from problems
 142 in accessing a remote file using ftp.@*
 143 @xref{Remote Files,,, emacs, The GNU Emacs Manual}.
 144
 145 @item invalid-function
 146 @code{"Invalid function"}@*
 147 @xref{Function Indirection}.
 148
 149 @item invalid-read-syntax
 150 @code{"Invalid read syntax"}@*
 151 @xref{Printed Representation}.
 152
 153 @item invalid-regexp
 154 @code{"Invalid regexp"}@*
 155 @xref{Regular Expressions}.
 156
 157 @c simple.el
 158 @item mark-inactive
 159 @code{"The mark is not active now"}@*
 160 @xref{The Mark}.
 161
 162 @item no-catch
 163 @code{"No catch for tag"}@*
 164 @xref{Catch and Throw}.
 165
 166 @ignore
 167 @c Not actually used for anything?  Probably definition should be removed.
 168 @item protected-field
 169 @code{"Attempt to modify a protected field"}
 170 @end ignore
 171
 172 @item scan-error
 173 @code{"Scan error"}@*
 174 This happens when certain syntax-parsing functions
 175 find invalid syntax or mismatched parentheses.@*
 176 @xref{List Motion}, and @ref{Parsing Expressions}.
 177
 178 @item search-failed
 179 @code{"Search failed"}@*
 180 @xref{Searching and Matching}.
 181
 182 @item setting-constant
 183 @code{"Attempt to set a constant symbol"}@*
 184 The values of the symbols @code{nil} and @code{t},
 185 and any symbols that start with @samp{:},
 186 may not be changed.@*
 187 @xref{Constant Variables, , Variables that Never Change}.
 188
 189 @c simple.el
 190 @item text-read-only
 191 @code{"Text is read-only"}@*
 192 This is a subcategory of @code{buffer-read-only}.@*
 193 @xref{Special Properties}.
 194
 195 @item undefined-color
 196 @code{"Undefined color"}@*
 197 @xref{Color Names}.
 198
 199 @item void-function
 200 @code{"Symbol's function definition is void"}@*
 201 @xref{Function Cells}.
 202
 203 @item void-variable
 204 @code{"Symbol's value as variable is void"}@*
 205 @xref{Accessing Variables}.
 206
 207 @item wrong-number-of-arguments
 208 @code{"Wrong number of arguments"}@*
 209 @xref{Classifying Lists}.
 210
 211 @item wrong-type-argument
 212 @code{"Wrong type argument"}@*
 213 @xref{Type Predicates}.
 214 @end table
 215
 216   The following kinds of error, which are classified as special cases of
 217 @code{arith-error}, can occur on certain systems for invalid use of
 218 mathematical functions.  @xref{Math Functions}.
 219
 220 @table @code
 221 @item domain-error
 222 @code{"Arithmetic domain error"}
 223
 224 @item overflow-error
 225 @code{"Arithmetic overflow error"}@*
 226 This is a subcategory of @code{domain-error}.
 227
 228 @item range-error
 229 @code{"Arithmetic range error"}
 230
 231 @item singularity-error
 232 @code{"Arithmetic singularity error"}@*
 233 This is a subcategory of @code{domain-error}.
 234
 235 @item underflow-error
 236 @code{"Arithmetic underflow error"}@*
 237 This is a subcategory of @code{domain-error}.
 238 @end table