DOCUMENT:Q11988 06-NOV-1999 [win16sdk] TITLE :Windows File I/O vs. C Run-time File I/O PRODUCT :Microsoft Windows Software Development Kit PROD/VER:WINDOWS:3.0,3.1 OPER/SYS: KEYWORDS:kb16bitonly ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 ------------------------------------------------------------------------------- SUMMARY ======= The following functions are provided by the Microsoft C Run-time Library (CRT) and the Windows API to create a file: Return Type API or Function Category -------------------------------------------- HFILE OpenFile Windows API HFILE _lopen/_lcreat Windows API int _open/_creat CRT FILE * fopen CRT These return types (HFILE, int, and FILE *) are not compatible, so they can not be used in a function which is expecting the other type. The HFILEs are handles to operating system files (MS-DOS file handles), the ints are CRT file handles, and the FILE *s are pointers to structures which represent a CRT stream. For files opened with OpenFile(), _lopen, and _lcreat, the common file manipuluation routines that you should use are: _lclose _llseek _lread _lwrite For files opened with _open() and _creat(), the common file manipulation routines that you should use are: _close _lseek _read _write For files opened with fopen, the common file manipulation routines that you should use are: fclose fseek fread fwrite For other input and output functions, please check the documentation for information on whether they are intended for use with MS-DOS handles (HFILE), streams (FILE *), or low-level I/O (int). MORE INFORMATION ================ An application should use the OpenFile() API any time an MS-DOS file handle is required. The open functions do not necessarily open a file in binary raw mode; the application is required to set the binary attribute explicitly. The OpenFile() function automatically performs this step. If the filename parameter specifies only a filename and extension, the open functions search for a matching file only in the current directory. In Windows, the OpenFile() API creates an MS-DOS file handle through which an application can access Windows-specific files. OpenFile() initially opens the file in binary raw mode by performing an MS-DOS Interrupt 21h Function 3Dh. If the lpFileName parameter specifies only a filename and an extension, OpenFile() searches for a matching file in the following directories: - The current directory. - The Windows directory. The GetWindowsDirectory() API returns the path to this directory. - The Windows system directory . The GetSystemDirectory() API returns the path to this directory. - The directories listed in the PATH environment variable. Additional query words: 3.00 3.10 ====================================================================== Keywords : kb16bitonly Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310 Version : WINDOWS:3.0,3.1 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.