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From: hxd9622@ritcv.UUCP
Newsgroups: net.unix-wizards
Subject: Help with tsearch (3C) in sysV
Message-ID: <9870@ritcv.UUCP>
Date: Fri, 18-Jul-86 03:53:49 EDT
Article-I.D.: ritcv.9870
Posted: Fri Jul 18 03:53:49 1986
Date-Received: Sun, 20-Jul-86 10:24:47 EDT
References: <2321@brl-smoke.ARPA>
Reply-To: hxd9622@ritcv.UUCP (Herman Darmawan)
Organization: Rochester Institute of Technology, Rochester, NY
Lines: 56
Keywords: sysV subroutines...
Summary: How do you use tsearch, tdelete, twalk?



[]

   I need help with some subroutines in sysV ie tsearch(3C) and tdelete(3C).

   Does anyone know how to use these routines? 
   How do you pass the parameters?

   I have declared the following struct...

   struct rec 
	{
	char *string;
	struct rec *left, *right;
	}

   tsearch is declared as...

   char *tsearch ((char *) key, (char **)rootp, compar)
   int (*compar)();

   I'm in a loop that reads a line of text and calls tsearch to insert
   line in the tree...

   while (fgets(line, MAXLINE, file))
	
	ptr = (struct rec *)tsearch((char *)line, (char *)root, strcompar);

   Note:
	ptr should point to the node containing line in the binary tree.
	root will point to new node if NULL.
	strcompar SCfunction to compar 2 strings.
	(char *)root == (char **)&root (isn't it?)

   I don't understand the first argument to tsearch..

        (char *)key - what is key?
		      is it the field contents - a string?
		      or is it a ptr to new node with new string in it?

   I wrote my own routines for these but I need these routines for something
   bigger.  When I used my own routines, everything worked fine.
   Can anyone help?  Thanks a million!

   PS
	just in case Pnews doesn't ask for
	my .signature...

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Herman Darmawan @ Rochester Institute of Technology
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BITNET   HND9622@RITVAXC

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