#include #include #include #include int main(int argc, char * argv[]) { if (argc < 2 ){ fprintf(stderr, "usage: test-lock LOCKPATH\n"); return 1; } int fd = open(argv[1],O_RDWR|O_CREAT|O_EXCL); if (fd < 0) { if (errno == EEXIST) { fprintf(stderr, "Lock is already held.\n"); return 0; } else { fprintf(stderr, "Some other error? %d = %s\n", errno, strerror(errno)); return 1; } } else { fprintf(stderr, "I have the lock, the fd is %d.\n", fd); fprintf(stderr, "Press Enter to release lock.\n"); while (!feof(stdin) && fgetc(stdin) != '\n') { /* nothing */ } close(fd); unlink(argv[1]); return 0; } }