/* ECP: FILEname=fig13_11.c */
/* 1*/   /* Copy From SrcFile To DestFile */
/* 2*/   /* Return Number Of Characters Copied, -1 For Errors */

/* 3*/   #include <stdio.h>
/* 4*/   #include <sys/stat.h>
/* 5*/   #include <fcntl.h>
/* 6*/   #include <sys/unistd.h>
/* 7*/   #include <string.h>
/* 8*/   #include <errno.h>

/* 9*/   #define BufSize 8192

/*10*/   long int
/*11*/   Copy( const char *DestFile, const char *SrcFile )
/*12*/   {
/*13*/       long int CharsRead, CharsCounted = 0;
/*14*/       int SrcDesc, DestDesc;
/*15*/       char Buffer[ BufSize ];
/*16*/       const CreateFlag =  O_WRONLY | O_CREAT | O_TRUNC;
/*17*/       const Mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;

/*18*/       if( strcmp( SrcFile, DestFile ) == 0 )
/*19*/       {
/*20*/           fprintf( stderr, "Can not copy to self\n" );
/*21*/           return -1L;
/*22*/       }

/*23*/       if( ( SrcDesc = open( SrcFile, O_RDONLY ) ) < 0 )
/*24*/       {
/*25*/           perror( SrcFile );
/*26*/           return -1L;
/*27*/       }
/*28*/       if( ( DestDesc = open( DestFile, CreateFlag, Mode ) ) < 0 )
/*29*/       {
/*30*/           perror( DestFile );
/*31*/           return -1L;
/*32*/       }

/*33*/       while( ( CharsRead = read( SrcDesc, Buffer, BufSize ) ) > 0 )
/*34*/           if( write( DestDesc, Buffer, CharsRead ) < CharsRead )
/*35*/           {
/*36*/               perror( DestFile );
/*37*/               break;
/*38*/           }
/*39*/           else
/*40*/               CharsCounted += CharsRead;

/*41*/       close( SrcDesc ); close( DestDesc );
/*42*/       return CharsCounted;
/*43*/   }