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1 ## Copyright (C) 2014 John W. Eaton |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## -*- texinfo -*- |
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20 ## @deftypefn {Built-in Function} {} usage (@var{msg}) |
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21 ## |
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22 ## @code{usage} is deprecated and will be removed in Octave version 4.6. |
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23 ## Please use @code{print_usage} in all new code. |
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24 ## |
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25 ## Print the message @var{msg}, prefixed by the string @samp{usage: }, and |
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26 ## set Octave's internal error state such that control will return to the |
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27 ## top level without evaluating any more commands. This is useful for |
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28 ## aborting from functions. |
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29 ## |
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30 ## After @code{usage} is evaluated, Octave will print a traceback of all |
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31 ## the function calls leading to the usage message. |
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32 ## |
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33 ## You should use this function for reporting problems errors that result |
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34 ## from an improper call to a function, such as calling a function with an |
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35 ## incorrect number of arguments, or with arguments of the wrong type. For |
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36 ## example, most functions distributed with Octave begin with code like |
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37 ## this |
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38 ## |
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39 ## @example |
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40 ## @group |
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41 ## if (nargin != 2) |
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42 ## usage (\"foo (a, b)\"); |
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43 ## endif |
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44 ## @end group |
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45 ## @end example |
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46 ## |
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47 ## @noindent |
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48 ## to check for the proper number of arguments. |
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49 ## @seealso{print_usage} |
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50 ## @end deftypefn |
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51 |
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52 ## Deprecated in version 4.2 |
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53 |
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54 function retval = usage (varargin) |
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55 |
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56 persistent warned = false; |
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57 if (! warned) |
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58 warned = true; |
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59 warning ("Octave:deprecated-function", |
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60 "usage is obsolete and will be removed from a future version of Octave, please use print_usage instead"); |
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61 endif |
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62 |
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63 retval = __usage__ (varargin{:}); |
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64 |
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65 endfunction |
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66 |
