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 @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 The message is @samp{error}.  @xref{Errors}.
  41
  42 @item quit
  43 The message is @samp{Quit}.  @xref{Quitting}.
  44
  45 @item args-out-of-range
  46 The message is @samp{Args out of range}.  This happens when trying to
  47 access an element beyond the range of a sequence, buffer, or other
  48 container-like object.  @xref{Sequences Arrays Vectors}, and
  49 @xref{Text}.
  50
  51 @item arith-error
  52 The message is @samp{Arithmetic error}.  This occurs when trying to
  53 perform integer division by zero.  @xref{Numeric Conversions}, and
  54 @xref{Arithmetic Operations}.
  55
  56 @item beginning-of-buffer
  57 The message is @samp{Beginning of buffer}.  @xref{Character Motion}.
  58
  59 @item buffer-read-only
  60 The message is @samp{Buffer is read-only}.  @xref{Read Only Buffers}.
  61
  62 @item circular-list
  63 The message is @samp{List contains a loop}.  This happens when a
  64 circular structure is encountered.  @xref{Circular Objects}.
  65
  66 @item cl-assertion-failed
  67 The message is @samp{Assertion failed}.  This happens when the
  68 @code{assert} macro fails a test.  @xref{Assertions,,, cl, Common Lisp
  69 Extensions}.
  70
  71 @item coding-system-error
  72 The message is @samp{Invalid coding system}.  @xref{Lisp and Coding
  73 Systems}.
  74
  75 @item cyclic-function-indirection
  76 The message is @samp{Symbol's chain of function indirections contains
  77 a loop}.  @xref{Function Indirection}.
  78
  79 @item cyclic-variable-indirection
  80 The message is @samp{Symbol's chain of variable indirections contains
  81 a loop}.  @xref{Variable Aliases}.
  82
  83 @item dbus-error
  84 The message is @samp{D-Bus error}.  This is only defined if Emacs was
  85 compiled with D-Bus support.  @xref{Errors and Events,,, dbus, D-Bus
  86 integration in Emacs}.
  87
  88 @item end-of-buffer
  89 The message is @samp{End of buffer}.  @xref{Character Motion}.
  90
  91 @item end-of-file
  92 The message is @samp{End of file during parsing}.  Note that this is
  93 not a subcategory of @code{file-error}, because it pertains to the
  94 Lisp reader, not to file I/O.  @xref{Input Functions}.
  95
  96 @item file-already-exists
  97 This is a subcategory of @code{file-error}.  @xref{Writing to Files}.
  98
  99 @item file-date-error
 100 This is a subcategory of @code{file-error}.  It occurs when
 101 @code{copy-file} tries and fails to set the last-modification time of
 102 the output file.  @xref{Changing Files}.
 103
 104 @item file-error
 105 We do not list the error-strings of this error and its subcategories,
 106 because the error message is normally constructed from the data items
 107 alone when the error condition @code{file-error} is present.  Thus,
 108 the error-strings are not very relevant.  However, these error symbols
 109 do have @code{error-message} properties, and if no data is provided,
 110 the @code{error-message} property @emph{is} used.  @xref{Files}.
 111
 112 @c jka-compr.el
 113 @item compression-error
 114 This is a subcategory of @code{file-error}, which results from
 115 problems handling a compressed file.  @xref{How Programs Do Loading}.
 116
 117 @c userlock.el
 118 @item file-locked
 119 This is a subcategory of @code{file-error}.  @xref{File Locks}.
 120
 121 @c userlock.el
 122 @item file-supersession
 123 This is a subcategory of @code{file-error}.  @xref{Modification Time}.
 124
 125 @c net/ange-ftp.el
 126 @item ftp-error
 127 This is a subcategory of @code{file-error}, which results from
 128 problems in accessing a remote file using ftp.  @xref{Remote Files,,,
 129 emacs, The GNU Emacs Manual}.
 130
 131 @item invalid-function
 132 The message is @samp{Invalid function}.  @xref{Function Indirection}.
 133
 134 @item invalid-read-syntax
 135 The message is @samp{Invalid read syntax}.  @xref{Printed
 136 Representation}.
 137
 138 @item invalid-regexp
 139 The message is @samp{Invalid regexp}.  @xref{Regular Expressions}.
 140
 141 @c simple.el
 142 @item mark-inactive
 143 The message is @samp{The mark is not active now}.  @xref{The Mark}.
 144
 145 @item no-catch
 146 The message is @samp{No catch for tag}.  @xref{Catch and Throw}.
 147
 148 @ignore
 149 @c Not actually used for anything?  Probably definition should be removed.
 150 @item protected-field
 151 The message is @samp{Attempt to modify a protected fiel.
 152 @end ignore
 153
 154 @item scan-error
 155 The message is @samp{Scan error}.  This happens when certain
 156 syntax-parsing functions find invalid syntax or mismatched
 157 parentheses.  @xref{List Motion}, and @xref{Parsing Expressions}.
 158
 159 @item search-failed
 160 The message is @samp{Search failed}.  @xref{Searching and Matching}.
 161
 162 @item setting-constant
 163 The message is @samp{Attempt to set a constant symbol}.  This happens
 164 when attempting to assign values to @code{nil}, @code{t}, and keyword
 165 symbols.  @xref{Constant Variables}.
 166
 167 @c simple.el
 168 @item text-read-only
 169 The message is @samp{Text is read-only}.  This is a subcategory of
 170 @code{buffer-read-only}.  @xref{Special Properties}.
 171
 172 @item undefined-color
 173 The message is @samp{Undefined color}.  @xref{Color Names}.
 174
 175 @item void-function
 176 The message is @samp{Symbol's function definition is void}.
 177 @xref{Function Cells}.
 178
 179 @item void-variable
 180 The message is @samp{Symbol's value as variable is void}.
 181 @xref{Accessing Variables}.
 182
 183 @item wrong-number-of-arguments
 184 The message is @samp{Wrong number of arguments}.  @xref{Classifying
 185 Lists}.
 186
 187 @item wrong-type-argument
 188 The message is @samp{Wrong type argument}.  @xref{Type Predicates}.
 189 @end table
 190
 191 @ignore    The following seem to be unused now.
 192   The following kinds of error, which are classified as special cases of
 193 @code{arith-error}, can occur on certain systems for invalid use of
 194 mathematical functions.  @xref{Math Functions}.
 195
 196 @table @code
 197 @item domain-error
 198 The message is @samp{Arithmetic domain error}.
 199
 200 @item overflow-error
 201 The message is @samp{Arithmetic overflow error}.  This is a subcategory
 202 of @code{domain-error}.
 203
 204 @item range-error
 205 The message is @code{Arithmetic range error}.
 206
 207 @item singularity-error
 208 The mssage is @samp{Arithmetic singularity error}.  This is a
 209 subcategory of @code{domain-error}.
 210
 211 @item underflow-error
 212 The message is @samp{Arithmetic underflow error}.  This is a
 213 subcategory of @code{domain-error}.
 214 @end table
 215 @end ignore