GNU Octave Manual Version 3 by John W. Eaton, David Bateman, Søren Hauberg Paperback (6"x9"), 568 pages ISBN 095461206X RRP £24.95 ($39.95) |
12.2.2 Enabling and Disabling Warnings
The warning
function also allows you to control which warnings
are actually printed to the screen. If the warning
function
is called with a string argument that is either "on"
or "off"
all warnings will be enabled or disabled.
It is also possible to enable and disable individual warnings through their string identifications. The following code will issue a warning
warning ("non-negative-variable", "'a' must be non-negative. Setting 'a' to zero.");
while the following won't issue a warning
warning ("off", "non-negative-variable"); warning ("non-negative-variable", "'a' must be non-negative. Setting 'a' to zero.");
The functions distributed with Octave can issue one of the following warnings.
Octave:array-to-scalar
-
If the
Octave:array-to-scalar
warning is enabled, Octave will warn when an implicit conversion from an array to a scalar value is attempted. By default, theOctave:array-to-scalar
warning is disabled. Octave:array-to-vector
-
If the
Octave:array-to-vector
warning is enabled, Octave will warn when an implicit conversion from an array to a vector value is attempted. By default, theOctave:array-to-vector
warning is disabled. Octave:assign-as-truth-value
-
If the
Octave:assign-as-truth-value
warning is enabled, a warning is issued for statements likeif (s = t) ...
since such statements are not common, and it is likely that the intent was to writeif (s == t) ...
instead. There are times when it is useful to write code that contains assignments within the condition of awhile
orif
statement. For example, statements likewhile (c = getc()) ...
are common in C programming. It is possible to avoid all warnings about such statements by disabling theOctave:assign-as-truth-value
warning, but that may also let real errors likeif (x = 1) # intended to test (x == 1)! ...
slip by. In such cases, it is possible suppress errors for specific statements by writing them with an extra set of parentheses. For example, writing the previous example aswhile ((c = getc())) ...
will prevent the warning from being printed for this statement, while allowing Octave to warn about other assignments used in conditional contexts. By default, theOctave:assign-as-truth-value
warning is enabled. Octave:associativity-change
-
If the
Octave:associativity-change
warning is enabled, Octave will warn about possible changes in the meaning of some code due to changes in associativity for some operators. Associativity changes have typically been made for Matlab compatibility. By default, theOctave:associativity-change
warning is enabled. Octave:divide-by-zero
-
If the
Octave:divide-by-zero
warning is enabled, a warning is issued when Octave encounters a division by zero. By default, theOctave:divide-by-zero
warning is enabled. Octave:empty-list-elements
-
If the
Octave:empty-list-elements
warning is enabled, a warning is issued when an empty matrix is found in a matrix list. For example,a = [1, [], 3, [], 5]
By default, theOctave:empty-list-elements
warning is enabled. Octave:fortran-indexing
-
If the
Octave:fortran-indexing
warning is enabled, a warning is printed for expressions which select elements of a two-dimensional matrix using a single index. By default, theOctave:fortran-indexing
warning is disabled. Octave:function-name-clash
-
If the
Octave:function-name-clash
warning is enabled, a warning is issued when Octave finds that the name of a function defined in a function file differs from the name of the file. (If the names disagree, the name declared inside the file is ignored.) By default, theOctave:function-name-clash
warning is enabled. Octave:future-time-stamp
-
If the
Octave:future-time-stamp
warning is enabled, Octave will print a warning if it finds a function file with a time stamp that is in the future. By default, theOctave:future-time-stamp
warning is enabled. Octave:imag-to-real
-
If the
Octave:imag-to-real
warning is enabled, a warning is printed for implicit conversions of complex numbers to real numbers. By default, theOctave:imag-to-real
warning is disabled. Octave:matlab-incompatible
- Print warnings for Octave language features that may cause compatibility problems with Matlab.
Octave:missing-semicolon
-
If the
Octave:missing-semicolon
warning is enabled, Octave will warn when statements in function definitions don't end in semicolons. By default theOctave:missing-semicolon
warning is disabled. Octave:neg-dim-as-zero
-
If the
Octave:neg-dim-as-zero
warning is enabled, print a warning for expressions likeeye (-1)
By default, theOctave:neg-dim-as-zero
warning is disabled. Octave:num-to-str
-
If the
Octave:num-to-str
warning is enable, a warning is printed for implicit conversions of numbers to their ASCII character equivalents when strings are constructed using a mixture of strings and numbers in matrix notation. For example,[ "f", 111, 111 ] => "foo"
elicits a warning if theOctave:num-to-str
warning is enabled. By default, theOctave:num-to-str
warning is enabled. Octave:precedence-change
-
If the
Octave:precedence-change
warning is enabled, Octave will warn about possible changes in the meaning of some code due to changes in precedence for some operators. Precedence changes have typically been made for Matlab compatibility. By default, theOctave:precedence-change
warning is enabled. Octave:reload-forces-clear
-
If several functions have been loaded from the same file, Octave must
clear all the functions before any one of them can be reloaded. If
the
Octave:reload-forces-clear
warning is enabled, Octave will warn you when this happens, and print a list of the additional functions that it is forced to clear. By default, theOctave:reload-forces-clear
warning is enabled. Octave:resize-on-range-error
-
If the
Octave:resize-on-range-error
warning is enabled, print a warning when a matrix is resized by an indexed assignment with indices outside the current bounds. By default, theOctave:resize-on-range-error
warning is disabled. Octave:separator-insert
- Print warning if commas or semicolons might be inserted automatically in literal matrices.
Octave:single-quote-string
- Print warning if a single quote character is used to introduce a string constant.
Octave:str-to-num
-
If the
Octave:str-to-num
warning is enabled, a warning is printed for implicit conversions of strings to their numeric ASCII equivalents. For example,"abc" + 0 => 97 98 99
elicits a warning if theOctave:str-to-num
warning is enabled. By default, theOctave:str-to-num
warning is disabled. Octave:string-concat
-
If the
Octave:string-concat
warning is enabled, print a warning when concatenating a mixture of double and single quoted strings. By default, theOctave:string-concat
warning is disabled. Octave:undefined-return-values
-
If the
Octave:undefined-return-values
warning is disabled, print a warning if a function does not define all the values in the return list which are expected. By default, theOctave:undefined-return-values
warning is enabled. Octave:variable-switch-label
-
If the
Octave:variable-switch-label
warning is enabled, Octave will print a warning if a switch label is not a constant or constant expression. By default, theOctave:variable-switch-label
warning is disabled.
ISBN 095461206X | GNU Octave Manual Version 3 | See the print edition |