/* ftruncate.c - POSIX file truncation *//* Copyright 1984-1994 Wind River Systems, Inc. */#include "copyright_wrs.h"/*modification history--------------------01c,28jan94,dvs  doc changes01b,05jan94,kdl  general cleanup.01a,02nov93,dvs  written*//*DESCRIPTION: This module contains the POSIX compliant ftruncate() routine for truncating a file.INCLUDE FILES: unistd.hSEE ALSO:NOMANUAL*//* INCLUDES */#include "vxWorks.h"#include "unistd.h"#include "errno.h"#include "ioLib.h"#include "dosFsLib.h"/******************************************************************************** ftruncate - truncate a file (POSIX)** This routine truncates a file to a specified size. ** RETURNS: 0 (OK) or -1 (ERROR) if unable to truncate file.** ERRNO:*  EROFS *   - File resides on a read-only file system.*  EBADF*   - File is open for reading only.*  EINVAL*   - File descriptor refers to a file on which this operation is impossible.**/int ftruncate     (    int 	fildes,			/* fd of file to truncate */    off_t	length			/* length to truncate file */    )    {    int 	status;			/* status value from ioctl */    if ((status = ioctl (fildes, FIOTRUNC, length)) == ERROR)	{	/* map errno to that specified by POSIX */	switch (errno)            {	    case S_ioLib_WRITE_PROTECTED:		errno = EROFS;		break;	    case S_dosFsLib_READ_ONLY:		errno = EBADF;		break;	    case S_ioLib_UNKNOWN_REQUEST:	    default:		errno = EINVAL;		break;	    }	return (ERROR);	}    else 	return (OK);    }