SetEnvironmentVariable function

Sets the contents of the specified environment variable for the current process.

Syntax

BOOL WINAPI SetEnvironmentVariable(
  _In_     LPCTSTR lpName,
  _In_opt_ LPCTSTR lpValue
);

Parameters

lpName [in]

The name of the environment variable. The operating system creates the environment variable if it does not exist and lpValue is not NULL.

lpValue [in, optional]

The contents of the environment variable. The maximum size of a user-defined environment variable is 32,767 characters. For more information, see Environment Variables.

Windows Server 2003 and Windows XP:  The total size of the environment block for a process may not exceed 32,767 characters.

If this parameter is NULL, the variable is deleted from the current process's environment.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

This function has no effect on the system environment variables or the environment variables of other processes.

Examples

For an example, see Changing Environment Variables.

Requirements

See also

Environment Variables

GetEnvironmentVariable