Category : Files from Magazines
Archive   : CUJ9202.ZIP
Filename : 1002018A

 
Output of file : 1002018A contained in archive : CUJ9202.ZIP


Listing 6 -- the file xfspos.c

/* _Fspos function -- UNIX version */
#include
#include "xstdio.h"

/* UNIX system call */
long _Lseek(int, long, int);

int _Fspos(FILE *str, const fpos_t *ptr, long loff, int way)
{ /* position a file */
if (fflush(str))
{ /* write error */
errno = EFPOS;
return (EOF);
}
if (ptr)
loff += ((fpos_t *)ptr)->_Off; /* fsetpos */
if (way == SEEK_CUR && str->_Mode & _MREAD)
loff -= str->_Nback
? str->_Rsave - str->_Next + str->_Nback
: str->_Rend - str->_Next;
if (way == SEEK_CUR && loff != 0
|| way != SEEK_SET || loff != -1)
loff = _Lseek(str->_Handle, loff, way);
if (loff == -1)
{ /* request failed */
errno = EFPOS;
return (EOF);
}
else
{ /* success */
if (str->_Mode & (_MREAD|_MWRITE))
{ /* empty buffer */
str->_Next = str->_Buf;
str->_Rend = str->_Buf;
str->_Wend = str->_Buf;
str->_Nback = 0;
}
str->_Mode &= ~(_MEOF|_MREAD|_MWRITE);
return (0);
}
}