2 @c This is part of the GNU Emacs Lisp Reference Manual.
3 @c Copyright (C) 1990-1993, 1999, 2001-2018 Free Software Foundation,
5 @c See the file elisp.texi for copying conditions.
7 @appendix Standard Errors
8 @cindex standard errors
10 Here is a list of the more important error symbols in standard Emacs, grouped
11 by concept. The list includes each symbol's message and a cross reference
12 to a description of how the error can occur.
14 Each error symbol has an set of parent error conditions 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.
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.
26 Most of these error symbols are defined in C (mainly @file{data.c}),
27 but some are defined in Lisp. For example, the file @file{userlock.el}
28 defines the @code{file-locked} and @code{file-supersession} errors.
29 Several of the specialized Lisp libraries distributed with Emacs
30 define their own error symbols. We do not attempt to list of all
33 @xref{Errors}, for an explanation of how errors are generated and
38 The message is @samp{error}. @xref{Errors}.
41 The message is @samp{Quit}. @xref{Quitting}.
43 @item args-out-of-range
44 The message is @samp{Args out of range}. This happens when trying to
45 access an element beyond the range of a sequence, buffer, or other
46 container-like object. @xref{Sequences Arrays Vectors}, and
50 The message is @samp{Arithmetic error}. This occurs when trying to
51 perform integer division by zero. @xref{Numeric Conversions}, and
52 @xref{Arithmetic Operations}.
54 @item beginning-of-buffer
55 The message is @samp{Beginning of buffer}. @xref{Character Motion}.
57 @item buffer-read-only
58 The message is @samp{Buffer is read-only}. @xref{Read Only Buffers}.
61 The message is @samp{List contains a loop}. This happens when a
62 circular structure is encountered. @xref{Circular Objects}.
64 @item cl-assertion-failed
65 The message is @samp{Assertion failed}. This happens when the
66 @code{cl-assert} macro fails a test. @xref{Assertions,,, cl, Common Lisp
69 @item coding-system-error
70 The message is @samp{Invalid coding system}. @xref{Lisp and Coding
73 @item cyclic-function-indirection
74 The message is @samp{Symbol's chain of function indirections contains
75 a loop}. @xref{Function Indirection}.
77 @item cyclic-variable-indirection
78 The message is @samp{Symbol's chain of variable indirections contains
79 a loop}. @xref{Variable Aliases}.
82 The message is @samp{D-Bus error}. This is only defined if Emacs was
83 compiled with D-Bus support. @xref{Errors and Events,,, dbus, D-Bus
84 integration in Emacs}.
87 The message is @samp{End of buffer}. @xref{Character Motion}.
90 The message is @samp{End of file during parsing}. Note that this is
91 not a subcategory of @code{file-error}, because it pertains to the
92 Lisp reader, not to file I/O@. @xref{Input Functions}.
94 @item file-already-exists
95 This is a subcategory of @code{file-error}. @xref{Writing to Files}.
98 This is a subcategory of @code{file-error}. It occurs when
99 @code{copy-file} tries and fails to set the last-modification time of
100 the output file. @xref{Changing Files}.
103 We do not list the error-strings of this error and its subcategories,
104 because the error message is normally constructed from the data items
105 alone when the error condition @code{file-error} is present. Thus,
106 the error-strings are not very relevant. However, these error symbols
107 do have @code{error-message} properties, and if no data is provided,
108 the @code{error-message} property @emph{is} used. @xref{Files}.
111 This is a subcategory of @code{file-error}. It occurs when an
112 operation attempts to act on a file that is missing. @xref{Changing
116 @item compression-error
117 This is a subcategory of @code{file-error}, which results from
118 problems handling a compressed file. @xref{How Programs Do Loading}.
122 This is a subcategory of @code{file-error}. @xref{File Locks}.
125 @item file-supersession
126 This is a subcategory of @code{file-error}. @xref{Modification Time}.
129 @item file-notify-error
130 This is a subcategory of @code{file-error}. It happens, when a file
131 could not be watched for changes. @xref{File Notifications}.
135 This is a subcategory of @code{file-error}, which results from
136 problems in accessing a remote file using ftp. @xref{Remote Files,,,
137 emacs, The GNU Emacs Manual}.
139 @item invalid-function
140 The message is @samp{Invalid function}. @xref{Function Indirection}.
142 @item invalid-read-syntax
143 The message is @samp{Invalid read syntax}. @xref{Printed
147 The message is @samp{Invalid regexp}. @xref{Regular Expressions}.
151 The message is @samp{The mark is not active now}. @xref{The Mark}.
154 The message is @samp{No catch for tag}. @xref{Catch and Throw}.
157 @c Not actually used for anything? Probably definition should be removed.
158 @item protected-field
159 The message is @samp{Attempt to modify a protected file}.
163 The message is @samp{Scan error}. This happens when certain
164 syntax-parsing functions find invalid syntax or mismatched
165 parentheses. Conventionally raised with three argument: a
166 human-readable error message, the start of the obstacle that cannot be
167 moved over, and the end of the obstacle. @xref{List Motion}, and
168 @xref{Parsing Expressions}.
171 The message is @samp{Search failed}. @xref{Searching and Matching}.
173 @item setting-constant
174 The message is @samp{Attempt to set a constant symbol}. This happens
175 when attempting to assign values to @code{nil}, @code{t},
176 @code{most-positive-fixnum}, @code{most-negative-fixnum}, and keyword
177 symbols. It also happens when attempting to assign values to
178 @code{enable-multibyte-characters} and some other symbols whose direct
179 assignment is not allowed for some reason. @xref{Constant Variables}.
183 The message is @samp{Text is read-only}. This is a subcategory of
184 @code{buffer-read-only}. @xref{Special Properties}.
186 @item undefined-color
187 The message is @samp{Undefined color}. @xref{Color Names}.
190 The message is the empty string. @xref{Signaling Errors}.
192 @item user-search-failed
193 This is like @samp{search-failed}, but doesn't trigger the debugger,
194 like @samp{user-error}. @xref{Signaling Errors}, and @xref{Searching
195 and Matching}. This is used for searching in Info files, @xref{Search
199 The message is @samp{Symbol's function definition is void}.
200 @xref{Function Cells}.
203 The message is @samp{Symbol's value as variable is void}.
204 @xref{Accessing Variables}.
206 @item wrong-number-of-arguments
207 The message is @samp{Wrong number of arguments}. @xref{Argument List}.
209 @item wrong-type-argument
210 The message is @samp{Wrong type argument}. @xref{Type Predicates}.
213 @ignore The following seem to be unused now.
214 The following kinds of error, which are classified as special cases of
215 @code{arith-error}, can occur on certain systems for invalid use of
216 mathematical functions. @xref{Math Functions}.
220 The message is @samp{Arithmetic domain error}.
223 The message is @samp{Arithmetic overflow error}. This is a subcategory
224 of @code{domain-error}.
227 The message is @code{Arithmetic range error}.
229 @item singularity-error
230 The message is @samp{Arithmetic singularity error}. This is a
231 subcategory of @code{domain-error}.
233 @item underflow-error
234 The message is @samp{Arithmetic underflow error}. This is a
235 subcategory of @code{domain-error}.