+
+error:
+ free(buf);
+ return NULL;
+}
+
+static void destroy_buffer(struct buffer_info *buf)
+{
+ int result;
+
+ result = ustcomm_close_app(&buf->conn);
+ if(result == -1) {
+ WARN("problem calling ustcomm_close_app");
+ }
+
+ result = shmdt(buf->mem);
+ if(result == -1) {
+ PERROR("shmdt");
+ }
+
+ result = shmdt(buf->bufstruct_mem);
+ if(result == -1) {
+ PERROR("shmdt");
+ }
+
+ result = close(buf->file_fd);
+ if(result == -1) {
+ PERROR("close");
+ }
+
+ free(buf);
+}
+
+int unwrite_last_subbuffer(struct buffer_info *buf)
+{
+ int result;
+
+ result = ftruncate(buf->file_fd, buf->previous_offset);
+ if(result == -1) {
+ PERROR("ftruncate");
+ return -1;
+ }
+
+ result = lseek(buf->file_fd, buf->previous_offset, SEEK_SET);
+ if(result == (int)(off_t)-1) {
+ PERROR("lseek");
+ return -1;
+ }
+
+ return 0;