rewind.c

UNIX编程高级环境（第二版）的网络套接字部分的程序源码

#include    "db.h"

/* Rewind the index file for db_nextrec().
 * Automatically called by db_open().
 * Must be called before first db_nextrec().
 */

void
db_rewind(DB *db)
{
    off_t    offset;

    offset = (db->nhash + 1) * PTR_SZ;        /* +1 for free list ptr */

        /* We're just setting the file offset for this process
           to the start of the index records; no need to lock.
           +1 below for newline at end of hash table. */

    if ( (db->idxoff = lseek(db->idxfd, offset+1, SEEK_SET)) == -1)
        err_dump("lseek error");
}