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From: moran@yale.UUCP
Newsgroups: comp.lang.c
Subject: Re: printf and variable length string format (asterisk)
Message-ID: <19361@yale-celray.yale.UUCP>
Date: Mon, 23-Nov-87 04:54:20 EST
Article-I.D.: yale-cel.19361
Posted: Mon Nov 23 04:54:20 1987
Date-Received: Wed, 25-Nov-87 21:55:56 EST
References: <692@zycad.UUCP>
Sender: root@yale.UUCP
Reply-To: moran@yale-zoo-suned.UUCP (William Moran)
Organization: Yale University Computer Science Dept, New Haven CT
Lines: 47

In article <692@zycad.UUCP> kjb@zycad.UUCP (Kevin Buchs) writes:
>
>I want to print out a string whose length I will not know ahead, and which
>is not null terminated.  I thought the following use of the asterisk
>precision delimiter would work:
>	
>char *a = "hello"; int i;
>for (i=0; i<6; i++) printf("%*s\n", i, a);
...some examples omitted
>
>Does the asterisk not work with the s descriptor?  Or, am I using it wrong.
>Is there another way to do this (except fwrite)?

I think the reason is that the i would specify the minimum field
width, and in this case, the field would always be larger than that.
Running this will show you what is really going on here.

main() {
 static char a[2] = "h";
 int i;

 for(i=0;i<6;i++)
  printf("foo%*s string\n",i,a);
  }

it looks like ->

fooh string
fooh string
foo h string
foo  h string
foo   h string
foo    h string

So, in answer to your question: no, * sets a min. width not the actual
width. Perhaps you should look at the BSD routines which deal with
strings which are not null terminated i.e. you could copy the string
segement into one which is null terminated and then print that, but
it isn't really clear to me whether printing the pieces is important
to you.

			  
			  William L. Moran Jr.
moran@{yale.arpa, cs.yale.edu, yalecs.bitnet}  ...{ihnp4!hsi,decvax}!yale!moran

Gonna get my PhD...I'm a teenage lobotomy!
				- The Ramones