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