Hello~ I can't solove this exercise problem. I sutdy Unix System Programming by Keith Haviland, Edition 2.

That textbook has a example about exercise 3.10. I think, If this example is something changed, i can slove it.

but i can't solve. please help me. This programming should coding by C language.

Exexercise 3.10 (in Unix system programming by Keith Haviland, Dina Gray)

Write a program 'slowwatch' which periodically monitors the modification time of a named file(it should not fail if the file does not initially exist). When the file changes, 'slowwatch' should copy it to its standard output. How can you ensure (or guess) that the file is fully updated before it is copied?

Example /* lookout --print message when file changes */

#include

#include

#include

#define MFILE 10

void cmp(const char *, time_t);

struct stat sb;

main(int argc, char **argv){

int j;

time_t last_time[MFILE+1];

if(argc<2){

fprintf(stderr, "usage: lookout filename ... ");

exit(1);

}

if(--argc>MFILE){

fprintf(stderr, "lookout: too many filenames ");

exit(1);

}

/*initialization*/

for(j=1;j

if(stat(argv[j], &sb) == -1){

fprintf("stderr, "lookout: couldn't stat %s ", argv[j]);

exit(1);

}

last_time[j] = sb.st_mtime;

}

/* loop until file changes */

for(;;){

for(j=1;j<=argc;j++)

cmp(argv[j], last_time[j]);

/*

* rest for 60 seconds

* "sleep" is a standard

* UNIX library routine

*/

sleep(60);

}

}

void cmp(const char *name, time_t last){

/* as long as statistics about the file can be read

* check the modification time */

if(stat(name, &sb) ==- -1 || sb.st_mtime != last){

fprintf(stderr, "lookout: %s changed ", name);

eixt(0);

}

}