The message is to let you know that there will be something printed, that is the second argument to fprint. Most MATLAB commands do not print things directly to the screen or can be suppressed when terminated with a “;”. As of particular note here is that the behavior is different with a no output from a single ouptut. Of course that doesn’t help explain the message. I have brought that to the team’s attention.

>> s=fprintf(1, ‘Hi There\n’)
Hi There
s =
9
>> %Ok, but:
>> fprintf(1, ‘Hi There\n’)
Hi There
>>

You have to admit that the M-lint message in this case is worded a little oddly:
“This call of FPRINTF will produce output that will be printed.”

I can imaging people thinking ‘Duh, that’s why I called FPRINTF – to have output ‘printed’ to a file!’

Couldn’t it just use the standard ‘Terminate statement semicolon to prevent output’? In both cases, both messages might be a little clearer if they said ‘…prevent output to the command line.’

That is exactly why there is a message, because you aren’t expecting fprintf to return the number of bytes written. If you run your code, you will see an output from the fprintf function. Terminate with a semicolon, and you’ll be good to go.

I am getting the …

“This call of FPRINTF will produce output that will be printed.”

… M-Ling message. This is my code:

fprintf(fid,'*SECTION      3\n')

I know I am printing that into the file with FID, but why
get a warning for this? Thanks for clearing this up in advance.

Are you thinking of the message: “This call of will produce output that will be printed.” ?

I just wonder why there is no M-lint message for fclose or fprintf. It is common to see numbers displayed in the command window because we have forgotten the coma separator ; after a fclose(fid) or a fprint(fid,…)

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