Question

Can you use shared memory to communicate between php scripts and c program in windows?

The c program runs all the time and uses memory mapped files ie:

handle1 = CreateFileMapping(
 (HANDLE)0xFFFFFFFF, NULL, PAGE_READWRITE, 0, sizeof(byte)*BUFFER_SIZE, "my_foo" );

hView = (LPINT) MapViewOfFile(handle1, FILE_MAP_ALL_ACCESS, 0, 0, 0);

For the PHP scripts can I just use the below code to open the memory mapped file created by the c program?

$shmkey = @shmop_open(ftok("my_foo", 'R'), "a", 0644, $buffer_size);

or are c memory mapped files and php shared memory different things?

Answer 1

The PHP shmop functions are just wrappers for the underlying POSIX functions, which doesn’t seem to be available under windows.

From the PHP manual:

Note: Versions of Windows previous to Windows 2000 do not
support shared memory. Under Windows,
Shmop will only work when PHP is
running as a web server module, such
as Apache or IIS (CLI and CGI will not
work).

Appearently PHP emulates this behaviour within apache, but since it isn’t available in the stand alone binaries it will hardly integrate with the windows equivalents.