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Mail Archives: cygwin/1999/02/16/13:27:10

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Message-ID: <19990216132732.28101.rocketmail@send102.yahoomail.com>
Date: Tue, 16 Feb 1999 05:27:32 -0800 (PST)
From: Earnie Boyd <earnie_boyd AT yahoo DOT com>
Reply-To: earnie_boyd AT yahoo DOT com
Subject: Re: Cygwin B20 - fseek under gcc fails to reposition on text files
To: kabal AT ECE DOT McGill DOT CA
Cc: cygwin users <cygwin AT sourceware DOT cygnus DOT com>
MIME-Version: 1.0

You need to read the docs about "text mode processing".  This is
exactly the expected behavior.  If you're going to use these functions
then you must process in binary mode.

Regards,
Earnie.

---Peter Kabal <kabal AT ECE DOT McGill DOT CA> wrote:
>
> Consider a text file (CR/LF line endings).  Read a line, save the
> current position, seek to end-of-file, seek to the saved position,
> read a line.  The second read does not return the second line of
> the file.
> 
> A shell script which tests the problem is included below:
> ---------------------------------------------------------------------
> #!/bin/sh
> #
> # Test fseek bug
> # On Cygwin 20.1, a file is not correctly repositioned after seeking
to the
> # end-of-file on a text file (CR/LF line endings).
> 
> cat > tfrepos.c << EoF
> #include <stdio.h>
> int main (int argc, char *argv[])
> {
>   FILE *fp;
>   long int pos, size;
>   char line[200];
>   char *p;
> 
>   fp = fopen (argv[1], "r");
>   p = fgets (line, 200, fp);
>   printf (" Line: %s", p);
> 
>   pos = ftell (fp);
>   fseek (fp, 0L, SEEK_END);
>   fseek (fp, pos, SEEK_SET);
> 
>   p = fgets (line, 200, fp);
>   printf (" Line: %s", p);
> 
>   return 0;
> }
> EoF
> 
> # Run the test program with the c-program as input
> gcc tfrepos.c -o tfrepos
> ./tfrepos tfrepos.c
> 
> # Clean up
> rm -f tfrepos tfrepos.c
> ---------------------------------------------------------------------
> 
> Peter Kabal  kabal AT ECE DOT McGill DOT CA
> Dept. Electrical & Computer Eng.
> McGill University 
> 

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