Path: utzoo!attcan!uunet!zephyr.ens.tek.com!uw-beaver!rice!cs.utexas.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!uupsi!njin!princeton!phoenix!subbarao
From: subbarao@phoenix.Princeton.EDU (Kartik Subbarao)
Newsgroups: comp.unix.questions
Subject: Re: C to Shell -- Summary and another question
Message-ID: <16908@phoenix.Princeton.EDU>
Date: 31 May 90 20:58:45 GMT
References: <23498@adm.BRL.MIL>
Reply-To: subbarao@phoenix.Princeton.EDU (Kartik Subbarao)
Lines: 41

In article <23498@adm.BRL.MIL> rose@baby.swmed.utexas.edu (Rose Oguz) writes:
>
>So, I used
>	char f_names[20]; /* Make this 21 */
>	char *ret_stat;
>	long stat;
>	FILE *fp;
>	...
>	if ((fp = popen("ls *c", "r") != NULL) 
  	/* Need an extra ')' here ---^ */
	{
 	/* Ugly fscanf code deleted */
>	  while ((ret_stat=fgets(f_names, 2, fp)) != NULL)
>		                      /* ^^^ 2?! Don't you mean 20? */
	}
>	pclose(fp);
>
>
>Neither seems to work.  A file pointer is returned, but the while loop
>is never executed.  For the fscanf, -1 (EOF) is returned and for the
>fgets, NULL (also, EOF since I opened the file with popen) is
>returned.  I'm running this in my source directory; so, I know that
>files exist.  What am I doing wrong?  Any ideas?

I have no idea how this passed the compiling stage of your computer. The way
it looks now, its as if you are saying fp = (popen("ls *c", "r") != NULL),
because != has higher precedence than =. And so our compiler will gripe 
because you are trying to assign the value of int to a FILE *.

As to fgets, it should now work -- I hope you meant 20 instead of 2!


		-Just another popen() hacker,
	  	 Kartik


			
-- 
subbarao@{phoenix,bogey or gauguin}.Princeton.EDU -|Internet
kartik@silvertone.Princeton.EDU (NeXT mail)       -|	
subbarao@pucc.Princeton.EDU		          - Bitnet