Input and Output - Java - page 410

The C program in Example 10-10 writes the file random.dat that we read in Seeking to a
Position within a File . It uses the network byte order macros to make sure that the long in-
teger (32 bits on most C compilers) is in the correct order to be read as an int in Java:

Example 10-10. src/main/java/io/WriteRandom.c
/* C Program to create the random-access file for the RandomAccessFile example
* Ian F. Darwin, http://www.darwinsys.com/
*/

#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <machine/endian.h>

const const off_t off_t OFFSET = 1234 ; // off_t is a C "typedef", usually == long integer

const const char char * FILENAME = "random.dat" ;

const const int int MODE = 0644 ;

const const char char * MESSAGE = "Ye have sought, and ye have found!\r\n \r\n" ;

int int

main ( int

int argc , char char ** argv ) {

int int fd ;

int

int java_offset ;

iif (( fd = creat ( FILENAME , MODE )) < 0 ) {
perror ( FILENAME );
return return 1 ;

}

/* Java's DataStreams etc. are defined to be in network byte order */
java_offset = htonl ( OFFSET );

iif ( write ( fd , & java_offset , sizeof sizeof java_offset ) < 0 ) {

perror ( "write" );
return return 1 ;

}

iif ( lseek ( fd , OFFSET , SEEK_SET ) < 0 ) {
perror ( "seek" );
return

return 1 ;

}

iif ( write ( fd , MESSAGE , strlen ( MESSAGE )) != strlen ( MESSAGE )) {