"help" does not work
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I noticed this in R2025B. "help <myfunction>" just displays two blank lines, not the comments on top of <myfunction.m>. This m-file is in a directory at the beginning of my path.
回答（1 个）
Matt J
2025-11-4，19:46
23 个评论
Ravi
2025-11-4，20:13
Thanks. When I type "wihch help" I get
C:\Program Files\MATLAB\R2025b\toolbox\matlab\helptools\help.m
seems like the legitimate one. Is it not the right one?
Matt J
2025-11-4，20:51
编辑：Matt J
2025-11-4，20:52
seems like the legitimate one. Is it not the right one?
It's the right one, but it is not what I was talking about. You have to open help.m and step through the code inside it line by line, until you see it call a function you recognize as one of your own personal mfiles.
It may also be helpful to test help() after activating the debugger with,
>>dbstop if caught error
from the command line.
Do you have the same problem when you use doc()?
Matt J
2025-11-4，22:50
编辑：Matt J
2025-11-4，22:50
Another, perhaps easier thing to try is restoredefaultpath, which will set the path back to its default state. Do this and see if help() works normally.
Ravi
about 11 hours 前
编辑：Ravi
about 11 hours 前
Thanks for all your suggestions. Nothing works!
- There is no error when using "help"
- It works fine with all functions except those I have defined myself.
- restoredefaultpath does nothing.
- "doc <myfunction>" takes forever to return to a prompt. It opens a browser window with blank lines.
- "doc <matlabfunction>" opens the help for that function in a browser window.
Steven Lord
about 10 hours 前
Please attach one such myfunction.m file with which you see this behavior. It's possible, given that you said "It works fine with all functions except those I have defined myself.", that there's something about the way you defined your help text in those files that causes help to display just blank lines.
Please attach the file rather than quoting it here, in case there's some non-printable characters (that appear as blanks / spaces) introduced by say writing the code in Microsoft Word and having it formatted by that program.
Ravi
about 10 hours 前
Here you are. I just created this in the MATLAB editor just to make sure it is a text file.It is in the current directory and I can run it. But "help" returns nothing.
Torsten
about 6 hours 前
编辑：Torsten
about 6 hours 前
Do you get the same output as below if you type
dbtype 'C:\Program Files\MATLAB\R2025b\toolbox\matlab\helptools\help.m'
for the first five lines of "help.m" on your computer ?
dbtype '/MATLAB/toolbox/matlab/helptools/help.m' 1:5
1 function [out, docTopic] = help(varargin)
2 % Help is helpful!
3 cleanup.cache = matlab.lang.internal.introspective.cache.enable; %#ok<STRNU>
4
5 process = matlab.internal.help.helpProcess(nargout, nargin, varargin);
Steven Lord
about 5 hours 前
dbtype 1:10 myfunction.m
1 function [out] = myfunction(in)
2 %
3 %[out] = myfunction(in)
4 %
5 % This is to test out help
6 %
7 %
8
9 out = in;
10
help myfunction
[out] = myfunction(in)
This is to test out help
To confirm, this is not the behavior you see on your machine for those two commands? Can you run that on your machine and copy and paste the output into a comment here?
Torsten
about 5 hours 前
And if you save the file "myfunction.m" as "myfunction.m" in your working directory and type
help myfunction.m
[out] = myfunction(in)
This is to test out help
blank lines are displayed - in contrast to what you get here ? Then either there is a second file "help.m" on your MATLAB path or the "help.m" under C:\Program Files\MATLAB\R2025b\toolbox\matlab\helptools\help.m is corrupted.
Ravi
about 5 hours 前
>> dbtype 1:10 myfunction.m
1 function [out] = myfunction(in)
2 %[out] = myfunction(in)
3 %
4 % This is to test out help
5 %
6 %
7
8 out = in;
9
Ravi
about 5 hours 前
>> dbtype help
1 function [out, docTopic] = help(varargin)
2 % Help is helpful!
3 cleanup.cache = matlab.lang.internal.introspective.cache.enable; %#ok<STRNU>
4
5 process = matlab.internal.help.helpProcess(nargout, nargin, varargin);
6 if isnumeric(process.inputTopic)
7 process.inputTopic = inputname(process.inputTopic);
8 end
9
10 try %#ok<TRYNC>
11 % no need to tell customers about internal errors
12
13 process.callerContext = matlab.lang.internal.introspective.IntrospectiveContext.caller;
14
15 process.getHelpText;
16
17 process.prepareHelpForDisplay;
18 end
19
20 if nargout > 0
21 out = process.helpStr;
22 if nargout > 1
23 docTopic = process.docLinks.referencePage;
24 if isempty(docTopic)
25 docTopic = process.docLinks.productName;
26 end
27 end
28 end
29 end
30
31 % Copyright 1984-2023 The MathWorks, Inc.
Ravi
about 5 hours 前
>> help help
help - Help for functions in Command Window
This MATLAB function displays the help text for the functionality
specified by name, such as a function, method, class, toolbox, variable,
or namespace.
Syntax
help name
help
Input Arguments
character vector | string scalar
Examples
Introduced in MATLAB before R2006a
Torsten
about 5 hours 前
编辑：Torsten
about 4 hours 前
What if you copy the function "help.m" from C:\ProgramFiles\MATLAB\R2025b\toolbox\matlab\helptools\ to your working directory and then execute
help("myfunction.m")
[out] = myfunction(in)
This is to test out help
? If this doesn't work, I think you will have to reinstall MATLAB R2025b.
If this doesn't work either, contact MATLAB Technical Support:
Torsten
about 4 hours 前
You checked whether the system requirements for MATLAB R2025b are fulfilled for your computer ?
Ravi
about 4 hours 前
As I suspected. I wasted time reinstalling it and it still has the same problem! Yes, the computer supports these requirements. Thanks for your help.
Oh well, maybe somebody from Mathworks can help. I have another computer on which I will install it and see if it has the same problem. Obviously it worked fine for you, so maybe there is something peculiar about this specific computer!
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