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sscanf: tab character in input string?

Posted on 2013-06-17
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Last Modified: 2013-06-17
Ah hello

I have the following code, not written by myself, designed to parse out field/value pairs from an INI file:
	char txt[100], tmp[100];
	strcpy(txt, "FIELD=VALUE");
	
	if (sscanf( txt, " \t%[^=]", tmp ) == 1)
	{
		// Do stuff with tmp
	}

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Now, being reasonably competent with what sscanf does, I find myself confused as to the explicit space and tab character in the input string.  Moreoever, with 'txt' not having any spaces or tab characters in it, I am surprised that 'tmp' still holds "VALUE" after the call.

Can someone explain what the \t and space could be for here please?

TIA
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Question by:mrwad99
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4 Comments
 
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Accepted Solution

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ozo earned 125 total points
ID: 39253236
since %[ supresses the usual skip of leading white space,  the  \t and space explicitly skip any amount of white space, including none
but it seems redundant to have both  \t and space
and tmp should hold "FIELD"  after the call, not "VALUE"
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Author Comment

by:mrwad99
ID: 39253282
Thanks!

*Sigh*, yes: Ozo sorry the value of tmp is of course FIELD.

Yes, according to http://linux.die.net/man/3/sscanf it seems that using [ will supress skipping of leading white space.  (Not that I doubted you, just for others reading :))

But why the explicit single space and \t?  I tried with just the space, and just the tab, and both worked the same...any idea?
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Expert Comment

by:ozo
ID: 39253296
perhaps the author did not know that either would suffice
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Author Closing Comment

by:mrwad99
ID: 39253322
Thank you very much :)
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