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   1 @c -*-texinfo-*-
   2 @c This is part of the GNU Emacs Lisp Reference Manual.
   3 @c Copyright (C) 1990-1993, 1999, 2001-2013 Free Software Foundation,
   4 @c Inc.
   5 @c See the file elisp.texi for copying conditions.
   6 @node Standard Errors
   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.  E.g., 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 The message is @samp{error}.  @xref{Errors}.
  42
  43 @item quit
  44 The message is @samp{Quit}.  @xref{Quitting}.
  45
  46 @item args-out-of-range
  47 The message is @samp{Args out of range}.  This happens when trying to
  48 access an element beyond the range of a sequence, buffer, or other
  49 container-like object.  @xref{Sequences Arrays Vectors}, and
  50 @xref{Text}.
  51
  52 @item arith-error
  53 The message is @samp{Arithmetic error}.  This occurs when trying to
  54 perform integer division by zero.  @xref{Numeric Conversions}, and
  55 @xref{Arithmetic Operations}.
  56
  57 @item beginning-of-buffer
  58 The message is @samp{Beginning of buffer}.  @xref{Character Motion}.
  59
  60 @item buffer-read-only
  61 The message is @samp{Buffer is read-only}.  @xref{Read Only Buffers}.
  62
  63 @item circular-list
  64 The message is @samp{List contains a loop}.  This happens when a
  65 circular structure is encountered.  @xref{Circular Objects}.
  66
  67 @item cl-assertion-failed
  68 The message is @samp{Assertion failed}.  This happens when the
  69 @code{cl-assert} macro fails a test.  @xref{Assertions,,, cl, Common Lisp
  70 Extensions}.
  71
  72 @item coding-system-error
  73 The message is @samp{Invalid coding system}.  @xref{Lisp and Coding
  74 Systems}.
  75
  76 @item cyclic-function-indirection
  77 The message is @samp{Symbol's chain of function indirections contains
  78 a loop}.  @xref{Function Indirection}.
  79
  80 @item cyclic-variable-indirection
  81 The message is @samp{Symbol's chain of variable indirections contains
  82 a loop}.  @xref{Variable Aliases}.
  83
  84 @item dbus-error
  85 The message is @samp{D-Bus error}.  This is only defined if Emacs was
  86 compiled with D-Bus support.  @xref{Errors and Events,,, dbus, D-Bus
  87 integration in Emacs}.
  88
  89 @item end-of-buffer
  90 The message is @samp{End of buffer}.  @xref{Character Motion}.
  91
  92 @item end-of-file
  93 The message is @samp{End of file during parsing}.  Note that this is
  94 not a subcategory of @code{file-error}, because it pertains to the
  95 Lisp reader, not to file I/O@.  @xref{Input Functions}.
  96
  97 @item file-already-exists
  98 This is a subcategory of @code{file-error}.  @xref{Writing to Files}.
  99
 100 @item file-date-error
 101 This is a subcategory of @code{file-error}.  It occurs when
 102 @code{copy-file} tries and fails to set the last-modification time of
 103 the output file.  @xref{Changing Files}.
 104
 105 @item file-error
 106 We do not list the error-strings of this error and its subcategories,
 107 because the error message is normally constructed from the data items
 108 alone when the error condition @code{file-error} is present.  Thus,
 109 the error-strings are not very relevant.  However, these error symbols
 110 do have @code{error-message} properties, and if no data is provided,
 111 the @code{error-message} property @emph{is} used.  @xref{Files}.
 112
 113 @c jka-compr.el
 114 @item compression-error
 115 This is a subcategory of @code{file-error}, which results from
 116 problems handling a compressed file.  @xref{How Programs Do Loading}.
 117
 118 @c userlock.el
 119 @item file-locked
 120 This is a subcategory of @code{file-error}.  @xref{File Locks}.
 121
 122 @c userlock.el
 123 @item file-supersession
 124 This is a subcategory of @code{file-error}.  @xref{Modification Time}.
 125
 126 @c net/ange-ftp.el
 127 @item ftp-error
 128 This is a subcategory of @code{file-error}, which results from
 129 problems in accessing a remote file using ftp.  @xref{Remote Files,,,
 130 emacs, The GNU Emacs Manual}.
 131
 132 @item invalid-function
 133 The message is @samp{Invalid function}.  @xref{Function Indirection}.
 134
 135 @item invalid-read-syntax
 136 The message is @samp{Invalid read syntax}.  @xref{Printed
 137 Representation}.
 138
 139 @item invalid-regexp
 140 The message is @samp{Invalid regexp}.  @xref{Regular Expressions}.
 141
 142 @c simple.el
 143 @item mark-inactive
 144 The message is @samp{The mark is not active now}.  @xref{The Mark}.
 145
 146 @item no-catch
 147 The message is @samp{No catch for tag}.  @xref{Catch and Throw}.
 148
 149 @ignore
 150 @c Not actually used for anything?  Probably definition should be removed.
 151 @item protected-field
 152 The message is @samp{Attempt to modify a protected file}.
 153 @end ignore
 154
 155 @item scan-error
 156 The message is @samp{Scan error}.  This happens when certain
 157 syntax-parsing functions find invalid syntax or mismatched
 158 parentheses.  @xref{List Motion}, and @xref{Parsing Expressions}.
 159
 160 @item search-failed
 161 The message is @samp{Search failed}.  @xref{Searching and Matching}.
 162
 163 @item setting-constant
 164 The message is @samp{Attempt to set a constant symbol}.  This happens
 165 when attempting to assign values to @code{nil}, @code{t}, and keyword
 166 symbols.  @xref{Constant Variables}.
 167
 168 @c simple.el
 169 @item text-read-only
 170 The message is @samp{Text is read-only}.  This is a subcategory of
 171 @code{buffer-read-only}.  @xref{Special Properties}.
 172
 173 @item undefined-color
 174 The message is @samp{Undefined color}.  @xref{Color Names}.
 175
 176 @item user-error
 177 The message is the empty string.  @xref{Signaling Errors}.
 178
 179 @item void-function
 180 The message is @samp{Symbol's function definition is void}.
 181 @xref{Function Cells}.
 182
 183 @item void-variable
 184 The message is @samp{Symbol's value as variable is void}.
 185 @xref{Accessing Variables}.
 186
 187 @item wrong-number-of-arguments
 188 The message is @samp{Wrong number of arguments}.  @xref{Classifying
 189 Lists}.
 190
 191 @item wrong-type-argument
 192 The message is @samp{Wrong type argument}.  @xref{Type Predicates}.
 193 @end table
 194
 195 @ignore    The following seem to be unused now.
 196   The following kinds of error, which are classified as special cases of
 197 @code{arith-error}, can occur on certain systems for invalid use of
 198 mathematical functions.  @xref{Math Functions}.
 199
 200 @table @code
 201 @item domain-error
 202 The message is @samp{Arithmetic domain error}.
 203
 204 @item overflow-error
 205 The message is @samp{Arithmetic overflow error}.  This is a subcategory
 206 of @code{domain-error}.
 207
 208 @item range-error
 209 The message is @code{Arithmetic range error}.
 210
 211 @item singularity-error
 212 The message is @samp{Arithmetic singularity error}.  This is a
 213 subcategory of @code{domain-error}.
 214
 215 @item underflow-error
 216 The message is @samp{Arithmetic underflow error}.  This is a
 217 subcategory of @code{domain-error}.
 218 @end table
 219 @end ignore