SetFileApisToOEM function (fileapi.h)

Causes the file I/O functions for the process to use the OEM character set code page. This function is useful for 8-bit console input and output operations.


void SetFileApisToOEM();

Return value



The file I/O functions whose code page is set by SetFileApisToOEM are those functions exported by KERNEL32.DLL that accept or return a file name. SetFileApisToOEM sets the code page per process, rather than per thread or per computer.

The SetFileApisToOEM function is complemented by the SetFileApisToANSI function, which causes the same set of file I/O functions to use the ANSI character set code page.

The 8-bit console functions use the OEM code page by default. All other functions use the ANSI code page by default. This means that strings returned by the console functions may not be processed correctly by other functions, and vice versa. For example, if the FindFirstFileA function returns a string that contains certain extended ANSI characters, and the 8-bit console functions are set to use the OEM code page, then the WriteConsoleA function will not display the string properly.

Use the AreFileApisANSI function to determine which code page the set of file I/O functions is currently using. Use the SetConsoleCP and SetConsoleOutputCP functions to set the code page for the 8-bit console functions.

To solve the problem of code page incompatibility, it is best to use Unicode for console applications. Console applications that use Unicode are much more versatile than those that use 8-bit console functions. Barring that solution, a console application can call the SetFileApisToOEM function to cause the set of file I/O functions to use OEM character set strings rather than ANSI character set strings. Use the SetFileApisToANSI function to set those functions back to the ANSI code page.

When dealing with command lines, a console application should obtain the command line in Unicode form and then convert it to OEM form using the relevant character-to-OEM functions. Note also that the array in the argv parameter of the command-line main function contains ANSI character set strings in this case.

In Windows 8 and Windows Server 2012, this function is supported by the following technologies.

Technology Supported
Server Message Block (SMB) 3.0 protocol Yes
SMB 3.0 Transparent Failover (TFO) Yes
SMB 3.0 with Scale-out File Shares (SO) Yes
Cluster Shared Volume File System (CsvFS) Yes
Resilient File System (ReFS) Yes


Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header fileapi.h (include Windows.h, WinBase.h)
Library Kernel32.lib
DLL Kernel32.dll

See also


File Management Functions