Logo

[code]
#include <windows.h>
#include <stdio.h>

#define MUTEX_NAME "mutex name here, anyname"
int main()
{
HANDLE hMutex = OpenMutex(MUTEX_ALL_ACCESS, FALSE, MUTEX_NAME);
if(hMutex == NULL)
{
// no duplicate instances found
hMutex = CreateMutex(NULL, FALSE, MUTEX_NAME);
}
else
{
// a duplicate was found
return 0;
}

printf("Created console\n");
getchar();
return 1;
}
[/code]

As you can see, there's OpenMuteX and CreateMuteX function that has been used.  To briefly explain this, OpenMuteX opens a handle to check whether a mutex has been created.  If it returns the value NULL, it means that no mutex of the current string has been created.  So when it is NULL, CreateMuteX is called to create the mutex with the string MUTEX_NAME that has been defined.  Leave a feedback if you feel that there's lack of information.