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#include <unistd.h> // fork, write, read, close, sleep
#include <fcntl.h> // open
#include <stdio.h> // perror
#include <sys/wait.h> // waitpid, WNOHANG
int main(int argc, char* argv[]) {
int f1 = open(argv[1], O_RDONLY);
if (f1 < 0) {
perror("open");
return 1;
}
int f2 = open(argv[2], O_WRONLY | O_CREAT | O_APPEND);
if (f2 < 0) {
perror("open");
return 2;
}
pid_t fpid = fork();
if (fpid == 0) { // in child
char buf;
while (read(f1, &buf, 1)) {
write(f2, &buf, 1);
sleep(1);
}
}
else {
int status = -2;
char buf = 'p';
while(status == -2) {
sleep(2);
write(f2, &buf, 1);
waitpid(fpid, &status, WNOHANG);
}
}
close(f1);
close(f2);
}
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