Windows Environment - QB64 Wiki

Windows Environment

From QB64 Wiki

Jump to: navigation, search

You can try to set environmental values for a program. The program doesn't affect anything other than itself and its child processes.

DECLARE DYNAMIC LIBRARY "kernel32" FUNCTION SetEnvironmentVariableA& (BYVAL lpName AS _OFFSET, BYVAL lpValue AS _OFFSET) FUNCTION GetLastError~& () END DECLARE DIM Nam AS STRING DIM Value AS STRING Nam = "CalkinsDeleteMe" + CHR$(0) Value = "CalkinsDeleteMe1" + CHR$(0) IF 0 = SetEnvironmentVariableA(_OFFSET(Nam), _OFFSET(Value)) THEN PRINT "SetEnvironmentVariableA failed. Error: 0x" + LCASE$(HEX$(GetLastError)) END END IF PRINT "Type 'set|more' into the console then 'exit' to close it" SLEEP 1 SHELL "cmd.exe" CLS PRINT "open another cmd.exe, and use 'set|more' to verify that the change was local." END

Public domain, Feb 2012, Michael Calkins
Note: The current user's account and related processes will only be affected by the environmental changes until program ends!
To verify that the values are reset, Run... 'cmd.exe' and type command 'set|more' to see the values after the program is done.


This program sets environment variables in the registry, for both the system, and the current user, then removes them:

'public domain, feb 2012, michael calkins CONST milliseconds = 5000 CONST HKEY_CURRENT_USER = &H80000001~& CONST HKEY_LOCAL_MACHINE = &H80000002~& CONST REG_SZ = 1 CONST KEY_ALL_ACCESS = &HF003F& CONST ERROR_SUCCESS = 0 CONST ERROR_ACCESS_DENIED = 5 CONST ERROR_TIMEOUT = &H5B4 CONST WM_SETTINGCHANGE = &H1A CONST HWND_BROADCAST = &HFFFF& DECLARE DYNAMIC LIBRARY "advapi32" FUNCTION RegOpenKeyExA& (BYVAL hKey AS _OFFSET, BYVAL lpSubKey AS _OFFSET, BYVAL ulOptions AS _UNSIGNED LONG, BYVAL samDesired AS _UNSIGNED LONG, BYVAL phkResult AS _OFFSET) FUNCTION RegCloseKey& (BYVAL hKey AS _OFFSET) FUNCTION RegSetValueExA& (BYVAL hKey AS _OFFSET, BYVAL lpValueName AS _OFFSET, BYVAL Reserved AS _UNSIGNED LONG, BYVAL dwType AS _UNSIGNED LONG, BYVAL lpData AS _OFFSET, BYVAL cbData AS _UNSIGNED LONG) FUNCTION RegDeleteValueA& (BYVAL hKey AS _OFFSET, BYVAL lpValueName AS _OFFSET) END DECLARE DECLARE DYNAMIC LIBRARY "user32" 'lParem is actually a LONG_PTR, but qb64 complains if I make it a LONG. FUNCTION SendMessageTimeoutA& (BYVAL hWnd AS _OFFSET, BYVAL Msg AS _UNSIGNED LONG, BYVAL wParam AS _UNSIGNED LONG, BYVAL lParam AS _OFFSET, BYVAL fuFlags AS _UNSIGNED LONG, BYVAL uTimeout AS _UNSIGNED LONG, BYVAL lpdwResult AS _OFFSET) END DECLARE DECLARE DYNAMIC LIBRARY "kernel32" FUNCTION GetLastError~& () END DECLARE DIM hKeySys AS _OFFSET DIM hKeyUsr AS _OFFSET DIM SubKey AS STRING DIM Value AS STRING DIM bData AS STRING DIM l AS LONG PRINT "Please open 'System Properties', click 'Advanced', and click 'Environment" PRINT "Variables'." PRINT PRINT "Press any key to add them." PRINT "Expect to get an error message if you aren't admin, but the user variable should" PRINT "still change." SLEEP: DO WHILE LEN(INKEY$): LOOP SubKey = "System\CurrentControlSet\Control\Session Manager\Environment" + CHR$(0) l = RegOpenKeyExA(HKEY_LOCAL_MACHINE, _OFFSET(SubKey), 0, KEY_ALL_ACCESS, _OFFSET(hKeySys)) IF l THEN PRINT "(hKeySys) RegOpenKeyExA failed. Error: 0x" + LCASE$(HEX$(l)) hKeySys = 0 ELSE Value = "CalkinsDeleteMeSys" + CHR$(0) bData = "DeleteMe2" + CHR$(0) l = RegSetValueExA(hKeySys, _OFFSET(Value), 0, REG_SZ, _OFFSET(bData), LEN(bData)) IF l THEN PRINT "RegSetValueExA failed. Error: 0x" + LCASE$(HEX$(l)) END END IF END IF SubKey = "Environment" + CHR$(0) l = RegOpenKeyExA(HKEY_CURRENT_USER, _OFFSET(SubKey), 0, KEY_ALL_ACCESS, _OFFSET(hKeyUsr)) IF l THEN PRINT "(hKeyUsr) RegOpenKeyExA failed. Error: 0x" + LCASE$(HEX$(l)) END END IF Value = "CalkinsDeleteMeUsr" + CHR$(0) bData = "DeleteMe3" + CHR$(0) l = RegSetValueExA(hKeyUsr, _OFFSET(Value), 0, REG_SZ, _OFFSET(bData), LEN(bData)) IF l THEN PRINT "RegSetValueExA failed. Error: 0x" + LCASE$(HEX$(l)) END END IF PRINT PRINT "Please wait while broadcasting the change." 'SubKey still contains "Environment"+chr$(0) IF 0 = SendMessageTimeoutA(HWND_BROADCAST, WM_SETTINGCHANGE, 0, _OFFSET(SubKey), 0, milliseconds, _OFFSET(l)) THEN PRINT "SendMessageTimeoutA failed. Error: 0x" + LCASE$(HEX$(GetLastError)) END IF PRINT PRINT "You might need to exit and reopen the 'Environment Variables' window." PRINT "Press any key to delete them." SLEEP: DO WHILE LEN(INKEY$): LOOP 'Value still contains "CalkinsDeleteMeUsr"+chr$(0) l = RegDeleteValueA(hKeyUsr, _OFFSET(Value)) IF l THEN PRINT "RegDeleteValueA failed. Error: 0x" + LCASE$(HEX$(l)) END IF l = RegCloseKey(hKeyUsr) IF l THEN PRINT "RegCloseKey failed. Error: 0x" + LCASE$(HEX$(l)) END END IF IF hKeySys THEN Value = "CalkinsDeleteMeSys" + CHR$(0) l = RegDeleteValueA(hKeySys, _OFFSET(Value)) IF l THEN PRINT "RegDeleteValueA failed. Error: 0x" + LCASE$(HEX$(l)) END IF l = RegCloseKey(hKeySys) IF l THEN PRINT "RegCloseKey failed. Error: 0x" + LCASE$(HEX$(l)) END END IF END IF PRINT PRINT "Please wait while broadcasting the change." 'SubKey still contains "Environment"+chr$(0) IF 0 = SendMessageTimeoutA(HWND_BROADCAST, WM_SETTINGCHANGE, 0, _OFFSET(SubKey), 0, milliseconds, _OFFSET(l)) THEN PRINT "SendMessageTimeoutA failed. Error: 0x" + LCASE$(HEX$(GetLastError)) END IF PRINT PRINT "You might need to exit and reopen the 'Environment Variables' window." PRINT "Please verify that they are deleted." END

Screenshot of Windows Environmental variables when program is run.
When prompted, open the "Environment Variables" window within System Properties(Control Panel - Performance and Maintenance - System - Advanced - Environment Variables) to see the changes or open a new cmd.exe console to see it.
Administrator privileges are required to change System-wide environmental values, but not current user account values.


It is recommended that programs NOT change Windows environmental settings without the user's approval!


See also:



Navigation:
Go to Keyword Reference - Alphabetical
Go to Keyword Reference - By usage
Go to Main WIKI Page
Personal tools