rewind.c

用Ｃ语言编的邮件系统（毕业论文）

#include	"mail.h"

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

void
mail_rewind(MAIL *mail)
{
	off_t	offset;

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