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/***
*lseek.c - OS/2 change file position
*
* Copyright (c) 1989-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines _lseek() - move the file pointer
*
*Revision History:
* 06-20-89 PHG Module created, based on asm version
* 03-12-90 GJF Made calling type _CALLTYPE2 (for now), added #include
* <cruntime.h> and fixed the copyright. Also, cleaned up
* the formatting a bit.
* 04-03-90 GJF Now _CALLTYPE1.
* 07-24-90 SBM Removed '32' from API names
* 08-14-90 SBM Compiles cleanly with -W3
* 09-28-90 GJF New-style function declarators.
* 12-04-90 GJF Appended Win32 version with #ifdef-s. It's probably
* worth coming back and doing a more complete merge later
* (much later).
* 12-04-90 SRW Changed to include <oscalls.h> instead of <doscalls.h>
* 12-06-90 SRW Changed to use _osfile and _osfhnd instead of _osfinfo
* 01-16-91 GJF ANSI naming.
* 02-07-91 SRW Changed to call _get_osfhandle [_WIN32_]
* 04-09-91 PNT Added _MAC_ conditional
* 02-13-92 GJF Replaced _nfile by _nhandle for Win32.
*
*******************************************************************************/
#include <cruntime.h>
#include <oscalls.h>
#include <os2dll.h>
#include <io.h>
#include <internal.h>
#include <stdlib.h>
#include <errno.h>
#include <msdos.h>
#include <stdio.h>
/***
*long _lseek(fh,pos,mthd) - move the file pointer
*
*Purpose:
* Moves the file pointer associated with fh to a new position.
* The new position is pos bytes (pos may be negative) away
* from the origin specified by mthd.
*
* If mthd == SEEK_SET, the origin in the beginning of file
* If mthd == SEEK_CUR, the origin is the current file pointer position
* If mthd == SEEK_END, the origin is the end of the file
*
* Multi-thread:
* _lseek() = locks/unlocks the file
* _lseek_lk() = does NOT lock/unlock the file (it is assumed that
* the caller has the aquired the file lock,if needed).
*
*Entry:
* int fh - file handle to move file pointer on
* long pos - position to move to, relative to origin
* int mthd - specifies the origin pos is relative to (see above)
*
*Exit:
* returns the offset, in bytes, of the new position from the beginning
* of the file.
* returns -1L (and sets errno) if fails.
* Note that seeking beyond the end of the file is not an error.
* (although seeking before the beginning is.)
*
*Exceptions:
*
*******************************************************************************/
#ifdef MTHREAD
/* define locking/validating lseek */
long _CALLTYPE1 _lseek (
int fh,
long pos,
int mthd
)
{
int r;
/* validate fh */
#ifdef _WIN32_
if ( (unsigned)fh >= (unsigned)_nhandle ) {
#else
if ((unsigned)fh >= (unsigned)_nfile) {
#endif
/* bad file handle */
errno = EBADF;
_doserrno = 0; /* not OS/2 error */
return -1;
}
_lock_fh(fh); /* lock file handle */
r = _lseek_lk(fh, pos, mthd); /* seek */
_unlock_fh(fh); /* unlock file handle */
return r;
}
/* define core _lseek -- doesn't lock or validate fh */
long _CALLTYPE1 _lseek_lk (
int fh,
long pos,
int mthd
)
{
ULONG newpos; /* new file position */
ULONG dosretval; /* OS/2 return value */
#else
/* define normal _lseek */
long _CALLTYPE1 _lseek (
int fh,
long pos,
int mthd
)
{
ULONG newpos; /* new file position */
ULONG dosretval; /* OS/2 return value */
/* validate fh */
#ifdef _WIN32_
if ( (unsigned)fh >= (unsigned)_nhandle ) {
#else
if ((unsigned)fh >= (unsigned)_nfile) {
#endif
/* bad file handle */
errno = EBADF;
_doserrno = 0; /* not OS/2 error */
return -1;
}
#endif
/* tell OS/2 to seek */
#ifdef _CRUISER_
#if SEEK_SET != FILE_BEGIN || SEEK_CUR != FILE_CURRENT || SEEK_END != FILE_END
#error Xenix and OS/2 seek constants not compatible
#endif
dosretval = DOSSETFILEPTR(fh, pos, mthd, &newpos);
#else /* ndef _CRUISER_ */
#ifdef _WIN32_
#if SEEK_SET != FILE_BEGIN || SEEK_CUR != FILE_CURRENT || SEEK_END != FILE_END
#error Xenix and Win32 seek constants not compatible
#endif
if ((newpos = SetFilePointer((HANDLE)_get_osfhandle(fh),
pos, NULL, mthd)) == -1)
dosretval = GetLastError();
else
dosretval = 0;
#else /* ndef _WIN32_ */
#ifdef _MAC_
TBD();
#else /* ndef _MAC_ */
#error ERROR - ONLY CRUISER, WIN32, OR MAC TARGET SUPPORTED!
#endif /* _MAC_ */
#endif /* _WIN32_ */
#endif /* _CRUISER_ */
if (dosretval) {
/* OS/2 error */
_dosmaperr(dosretval);
return -1;
}
_osfile[fh] &= ~FEOFLAG; /* clear the ctrl-z flag on the file */
return newpos; /* return */
}
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