Copy a file using UNIX-system calls Post: 302300880

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Top Forums Programming Copy a file using UNIX-system calls Post 302300880 by c_d on Wednesday 25th of March 2009 09:47:46 AM

03-25-2009

Registered User

Copy a file using UNIX-system calls

Code:

#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<stdlib.h>

int main( int argc,char *argv[] )
{
    char buf;
    int sourcefile,destfile,n;
    if(argc!=3)
    {
        write(STDOUT_FILENO,"prgm1 <sourcefile> <destination file>\n",50);   
        exit(1);
    }
    else
    {
         sourcefile=open(argv[1],O_RDONLY);
         if(sourcefile==-1)
         {
            perror("SOURCE FILE ERROR");
            exit(0);
         }
         else
         {
            destfile=open(argv[2],O_WRONLY | O_CREAT , 0641);
            if(destfile==-1)
            {
                perror("DESTINATION FILE ERROR");
                exit(0);
            }
            else
            {
                while((n=read(sourcefile,&buf,1)) != -1)
                {
                    write( destfile, &buf, 1 );
                }
                write(STDOUT_FILENO, "FILES COPIED\n" , 15);    
                close(sourcefile);
                close(destfile);
            }
        }
    }
    return 0;
}

the value returned by read() (n) never becomes -1 ? why?
Smilie

c_d

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LEARN ABOUT DEBIAN

graphics::primitive::insets

Graphics::Primitive::Insets(3pm)			User Contributed Perl Documentation			  Graphics::Primitive::Insets(3pm)

NAME

       Graphics::Primitive::Insets - Space between things

DESCRIPTION

       Graphics::Primitive::Insets represents the amount of space that surrounds something.  This object can be used to represent either padding
       or margins (in the CSS sense, one being inside the bounding box, the other being outside)

SYNOPSIS

	 use Graphics::Primitive::Insets;

	 my $insets = Graphics::Primitive::Insets->new({
	   top	   => 5,
	   bottom  => 5,
	   left    => 5,
	   right   => 5
	 });

METHODS

   Constructor
       new Creates a new Graphics::Primitive::Insets.

   Instance Methods
       as_array
	   Return these insets as an array in the form of top, right, bottom and left.

       bottom
	   Set/Get the inset from the bottom.

       equal_to
	   Determine if these Insets are equal to another.

       left
	   Set/Get the inset from the left.

       right
	   Set/Get the inset from the right.

       top Set/Get the inset from the top.

       zero
	   Sets all the insets (top, left, bottom, right) to 0.

AUTHOR

       Cory Watson, "<gphat@cpan.org>"

SEE ALSO

       perl(1)

COPYRIGHT &; LICENSE
       Copyright 2008-2010 by Cory G Watson.

       This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

perl v5.12.3							    2010-08-21					  Graphics::Primitive::Insets(3pm)

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