src/port/win32fseek.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * win32fseek.c
   4  *        Replacements for fseeko() and ftello().
   5  *
   6  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
   7  *
   8  * IDENTIFICATION
   9  *        src/port/win32fseek.c
  10  *
  11  *-------------------------------------------------------------------------
  12  */
  13
  14 #ifdef FRONTEND
  15 #include "postgres_fe.h"
  16 #else
  17 #include "postgres.h"
  18 #endif
  19
  20 #ifdef _MSC_VER
  21
  22 /*
  23  * _pgfseeko64
  24  *
  25  * Calling fseek() on a handle to a non-seeking device such as a pipe or
  26  * a communications device is not supported, and fseek() may not return
  27  * an error.  This wrapper relies on the file type to check which cases
  28  * are supported.
  29  */
  30 int
  31 _pgfseeko64(FILE *stream, pgoff_t offset, int origin)
  32 {
  33         DWORD           fileType;
  34         HANDLE          hFile = (HANDLE) _get_osfhandle(_fileno(stream));
  35
  36         fileType = pgwin32_get_file_type(hFile);
  37         if (errno != 0)
  38                 return -1;
  39
  40         if (fileType == FILE_TYPE_DISK)
  41                 return _fseeki64(stream, offset, origin);
  42         else if (fileType == FILE_TYPE_CHAR || fileType == FILE_TYPE_PIPE)
  43                 errno = ESPIPE;
  44         else
  45                 errno = EINVAL;
  46
  47         return -1;
  48 }
  49
  50 /*
  51  * _pgftello64
  52  *
  53  * Same as _pgfseeko64().
  54  */
  55 pgoff_t
  56 _pgftello64(FILE *stream)
  57 {
  58         DWORD           fileType;
  59         HANDLE          hFile = (HANDLE) _get_osfhandle(_fileno(stream));
  60
  61         fileType = pgwin32_get_file_type(hFile);
  62         if (errno != 0)
  63                 return -1;
  64
  65         if (fileType == FILE_TYPE_DISK)
  66                 return _ftelli64(stream);
  67         else if (fileType == FILE_TYPE_CHAR || fileType == FILE_TYPE_PIPE)
  68                 errno = ESPIPE;
  69         else
  70                 errno = EINVAL;
  71
  72         return -1;
  73 }
  74
  75 #endif                                                  /* _MSC_VER */