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Re: Request help -- odd sprintf, fprintf issue

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On 29/08/2016 07:58, dakupoto@gmail.com wrote:
> Could some C language guru please help ?
> I am using gcc on Fedora 18.
>
> I have a simple function to write formatted
> character strings to a text file, the snippet
> that is causing problem is:
>
> memset(b, 0, SLEN);
> sprintf(b, "%s%s%d%s%d%s%f%s",
>          "RS"," ",snode," ",enode," ",ld,"\n");
> fprintf(a, "%s", b);
> memset(b, 0, SLEN);
>
> Here, 'a' is the non-NULL pointer to a text file,
> 'b' is character array of size 32, and enode and
> snode are integers as 1, 2, ...
>
> The output looks is(for one particular run):
>
> S 1 2 50.00
>
> I do not understand what is causing the 'R' in
> 'RS' to not get printed

What happens if you replace the fprintf with printf?

What if, just before the above code, you write:

  fprintf(a,"<");

Do you get "<S 1 2 50.00" or "<RS 1 2 50.0"? (Or "RS 1 2 50.0" and it's 
the "<" that's missing.)

What is the return value of sprintf? (It should be the number of 
characters printed, which I think is 13 if "\n" is counted as one.)

Since the output is to a file, what do you use to look at the file? Do 
you get the same result if you look at a dump of the file? (As the "R" 
might somehow hidden or overwritten.)


-- 
Bartc

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Request help -- odd sprintf, fprintf issue dakupoto@gmail.com - 2016-08-28 23:58 -0700
  Re: Request help -- odd sprintf, fprintf issue gazelle@shell.xmission.com (Kenny McCormack) - 2016-08-29 08:09 +0000
  Re: Request help -- odd sprintf, fprintf issue Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-29 10:30 +0100
  Re: Request help -- odd sprintf, fprintf issue BartC <bc@freeuk.com> - 2016-08-29 10:48 +0100
  Re: Request help -- odd sprintf, fprintf issue Brett Dong <brett.browning.dong@gmail.com> - 2016-08-29 18:15 +0800
  Re: Request help -- odd sprintf, fprintf issue Dutch Ingraham <spikeheron@att.net> - 2016-08-29 08:21 -0500
  Re: Request help -- odd sprintf, fprintf issue Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2016-08-29 09:10 -0600
  Re: Request help -- odd sprintf, fprintf issue Keith Thompson <kst-u@mib.org> - 2016-08-29 10:27 -0700
    Re: Request help -- odd sprintf, fprintf issue Ike Naar <ike@iceland.freeshell.org> - 2016-08-29 19:51 +0000
      Re: Request help -- odd sprintf, fprintf issue Keith Thompson <kst-u@mib.org> - 2016-08-29 14:30 -0700
        Re: Request help -- odd sprintf, fprintf issue Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-08-30 10:56 +0100

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