Assembly code snippets
Details
| Title | Block multiple instances |
|---|---|
| Author | smurf |
| Submitted by: | smurf |
| Date added: | 2002-02-18 03:29:42 |
| Date modified: | 2002-02-21 01:14:02 |
Comments
This code snipet blocks multiple instances of your program. When you first start your application a mutex is created and isnt destroyed until you exit your application. All attempts to startup another instance is blocked.
Snippet
.data
;// important: change the text to something original
SingleInstance db "Only one Instance of Me Allowed",0
.data?
;// will be the mutex handle you will need to destroy this later
hMutex dd ?
.code
;// this code will be the very first code in your .code section
invoke CreateMutex,0,FALSE,addr SingleInstance ;// create a mutex
mov hMutex,eax ;// save the handle
invoke GetLastError ;// check for errors
.if eax == ERROR_ALREADY_EXISTS ;// if mutex exists already
invoke ExitProcess, 0 ;// exit program
.endif
;// destroy the handle to the mutex before you exit your application
.ELSEIF uMsg == WM_DESTROY
invoke CloseHandle,hMutex
;// important: change the text to something original
SingleInstance db "Only one Instance of Me Allowed",0
.data?
;// will be the mutex handle you will need to destroy this later
hMutex dd ?
.code
;// this code will be the very first code in your .code section
invoke CreateMutex,0,FALSE,addr SingleInstance ;// create a mutex
mov hMutex,eax ;// save the handle
invoke GetLastError ;// check for errors
.if eax == ERROR_ALREADY_EXISTS ;// if mutex exists already
invoke ExitProcess, 0 ;// exit program
.endif
;// destroy the handle to the mutex before you exit your application
.ELSEIF uMsg == WM_DESTROY
invoke CloseHandle,hMutex