What is the difference brwtween submit SAS command from command line and dm statement?

[whymath]

If I submit command "help help" from command line, there show matching results in help documentation:

Fine, that is what I am expect. But it hits no results if I type "dm 'help help';" and submit it from program editor:

What is the reason of this? Are they really differs on "help" window?

By the way, I am run SAS 9.4M5 on Win10 machine.

[ballardw]

There are some limitation as to window focus when a DM statement is issued. You really want to make sure to include the window name because not all commands are valid in every window.

To be reasonably sure of sending the command to proper window the window name should be the first parameter in a DM statement.

[RichardDeVen · Accepted solution]

Display Manager is a thick client with a lot of legacy things going on.  I think the differences you found between submitting DM 'HELP HELP' and issuing HELP HELP in the COMMAND Bar (or COMMAND Line) is not something of significant matter.

The Help window raised is owned by the SAS DM session process, so there is likely some behind the scenes windows messaging going on to execute some routine in MVADocWin.dll (found in folder "C:\Program Files\SASHome\SASHelpViewerforWindows\<version>, which also contains standalone program "SASDocViewer.exe", which no doubt uses the same dll)

You would need a powerful tool to examine the differences in the messages to understand why the DM "HELP HELP" does not properly pass the keyword to the doc system.  One possibility is that (internally) the DM command statement that the job supervisor hands off to the help statement executor uses a buffer that does not contain a zero-termination byte the dll routine expects, which could cause a keyword search term that has no match.

Indeed, the supposition is proven by submitting the command as a hexadecimal string literal containing the necessary zero-byte termination. (thanks Best String to Hex Converter Online to Convert Text to Hex. (codebeautify.org)

dm '68656c702068656c7000'x;

Unfortunately, the Help window will not be raised on top of all other windows, but it will be there

Note: Improperly formed commands submitted as hex string literals can crash your SAS Display Manager session.   This is a security issue for SAS because additional exploitation of DM statement by a blackhat coder could cause unintended code execution or data leakage.

Regards,

Richard DeVenezia

[whymath]

Impressive and very professional.

[whymath]

@RichardDeVen Richard, I tried you hex way, just fall into another trap:

%macro help(key);
%local _helpinhex_;
%let _help_=help &key.;

%do i=1 %to %length(&_help_.);
  %let _helpinhex_=&_helpinhex_.%qsysfunc(putc(%qsubstr(&_help_.,&i.,1),$hex2.));
%end;
%let _helpinhex00_=&_helpinhex_.00;
%put &_helpinhex00_.;
%put dm "&_helpinhex00_."x;
dm "&_helpinhex00_."x;
%mend;

%help(help);

I get the following messages in log:

68656C702068656C7000
dm "68656C702068656C7000"x
ERROR: Invalid hexadecimal constant string "68656C702068656C7000"x.

The "" on my SAS log window just show like " =". How do you think of that?

[RichardDeVen]

%qsysfunc is just introducing more noise to whatever you are attempting.  The macro quoting causes hidden demarcators to be in the _helpindex_ symbol value.  There are many excellent papers about macro quoting and the hidden secrets therein.

Instead, use the $HEX<len>. format to obtain the hex literal representation of a string.

%macro help(term);
  %local length helphex;

  %let length = %eval (10 + 2 * %length(&term));
  %let helphex = %sysfunc(putc(help &term, $hex&length..));

  dm "&helphex.00"x;  
%mend;

options mprint;
%help (help)

Happy coding whymath.

[whymath]

Awesome and thanks again, Richard, I'll learn about %qsysfunc more further.