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From: "Charlie Gordon" <gmane@chqrlie.org>
To: linux-c-programming@vger.kernel.org
Subject: Re: how to find the end of piped data?
Date: Tue, 14 Sep 2004 11:03:18 +0200	[thread overview]
Message-ID: <ci6c3e$mra$1@sea.gmane.org> (raw)
In-Reply-To: 41458643.7060907@sit.fraunhofer.de

Dear Richard,

The C library I/O functions are agnostic about whether stdin data is coming
from a file , a pipeor a character device.
getchar() will return EOF upon end of file, closing of the pipe by the
piping process, or end of stream.

Here is how you should write your scanner:

void scanin()
{
     int c;
     char tmpkey[1024];  /* or whatever size you want */
     int tmpcnt = 0;

    while ((c = getchar()) != EOF) {
        if (c == '\n') {
            tmpkey[tmpcnt] = '\0';
            /* perform whatever treatment you want on a line of input */
            handle_one_line(tmpkey);
            tmpcnt = 0;
       } else {
           if (tmpcnt < (int)sizeof(tmpkey) - 2) {
               rmpkey[tmpcnt++] = c;
           }
       }
}

You can also use fgets() and check for NULL as the indication for end of
stream, but you will get a slightly different behaviour on truncated lines.

Cheers,

Chqrlie.

main(){int
y=0,x;while(y!=6){x=(y==0)?101:((y==1)?45:((y==2)?97:((y==3)?120:((y==4)?101
:10))));putchar(x);y++;}}

You can simplify this further : one liners should be less than 80
characters!

main(){int
y=0;while(++y<7)putchar(y<2?101:y<3?45:y<4?97:y<5?120:y<6?101:10);}

You can reduce this even further ;-)






      parent reply	other threads:[~2004-09-14  9:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-13 11:36 how to find the end of piped data? Richard Sammet
2004-09-14  6:06 ` Eric Bambach
2004-09-14  8:10   ` Charlie Gordon
2004-09-14  8:45   ` Richard Sammet
2004-09-14  9:03 ` Charlie Gordon [this message]

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