---
name: "ACE_Shared_Memory_MM"
section: "3"
platform: "linux"
package: "libace-doc"
version: "5.0.7-4"
release: "Debian 2.2 (Potato)"
platforms: ["linux"]
url: "https://new.carta.tech/ACE_Shared_Memory_MM"
---

# ACE\_Shared\_Memory\_MM(3)

Shared memory wrapper based on MMAP.

## NAME

ACE\_Shared\_Memory\_MM -  Shared memory wrapper based on MMAP.

## SYNOPSIS

```
#include <ace/Shared_Memory_MM.h>
class ACE_Shared_Memory_MM : public ACE_Shared_Memory
{
  public:
    ACE_Shared_Memory_MM (void);
    ACE_Shared_Memory_MM (
        ACE_HANDLE handle,
        int length = -1,
        int prot = PROT_RDWR,
        int share = ACE_MAP_PRIVATE,
        char *addr = 0,
        off_t pos = 0
        );
    ACE_Shared_Memory_MM (
        LPCTSTR file_name,
        int len = -1,
        int flags = O_RDWR | O_CREAT,
        int mode = ACE_DEFAULT_FILE_PERMS,
        int prot = PROT_RDWR,
        int share = ACE_MAP_SHARED,
        char *addr = 0,
        off_t pos = 0
        );
    int open (
        ACE_HANDLE handle,
        int length = -1,
        int prot = PROT_RDWR,
        int share = ACE_MAP_PRIVATE,
        char *addr = 0,
        off_t pos = 0
        );
    int open (
        LPCTSTR file_name,
        int len = -1,
        int flags = O_RDWR | O_CREAT,
        int mode = ACE_DEFAULT_FILE_PERMS,
        int prot = PROT_RDWR,
        int share = ACE_MAP_SHARED,
        char *addr = 0,
        off_t pos = 0
        );
    const TCHAR *filename (void) const;
    virtual int close (void);
    virtual int remove (void);
    virtual void *malloc (size_t size = 0);
    virtual int free (void *p);
    virtual int get_segment_size (void) const;
    virtual ACE_HANDLE get_id (void) const;
    void dump (void) const;
    ACE_ALLOC_HOOK_DECLARE;
  private:
    ACE_Mem_Map shared_memory_;
};
```

## DESCRIPTION

This class provides a very simple-minded shared memory manager.  For more a powerful memory allocator please see ACE\_Malloc.

## Initialization and termination methods.

```
ACE_Shared_Memory_MM (void);
```

Default constructor.

```
ACE_Shared_Memory_MM (
    ACE_HANDLE handle,
    int length = -1,
    int prot = PROT_RDWR,
    int share = ACE_MAP_PRIVATE,
    char *addr = 0,
    off_t pos = 0
    );
```

Constructor.

```
ACE_Shared_Memory_MM (
    LPCTSTR file_name,
    int len = -1,
    int flags = O_RDWR | O_CREAT,
    int mode = ACE_DEFAULT_FILE_PERMS,
    int prot = PROT_RDWR,
    int share = ACE_MAP_SHARED,
    char *addr = 0,
    off_t pos = 0
    );
```

Constructor.

```
int open (
    ACE_HANDLE handle,
    int length = -1,
    int prot = PROT_RDWR,
    int share = ACE_MAP_PRIVATE,
    char *addr = 0,
    off_t pos = 0
    );
```

Open method.

```
int open (
    LPCTSTR file_name,
    int len = -1,
    int flags = O_RDWR | O_CREAT,
    int mode = ACE_DEFAULT_FILE_PERMS,
    int prot = PROT_RDWR,
    int share = ACE_MAP_SHARED,
    char *addr = 0,
    off_t pos = 0
    );
```

Open method.

```
const TCHAR *filename (void) const;
```

Return the name of file that is mapped (if any).

```
virtual int close (void);
```

Close down the shared memory segment.

```
virtual int remove (void);
```

Remove the shared memory segment and the underlying file.

## Allocation and deallocation methods.

```
virtual void *malloc (size_t size = 0);
```

Create a new chuck of memory containing size bytes.

```
virtual int free (void *p);
```

Free a chuck of memory allocated by ACE\_Shared\_Memory\_MM::malloc.

```
virtual int get_segment_size (void) const;
```

Return the size of the shared memory segment.

```
virtual ACE_HANDLE get_id (void) const;
```

Return the ID of the shared memory segment (i.e., an ACE\_HANDLE).

```
void dump (void) const;
```

Dump the state of an object.

```
ACE_ALLOC_HOOK_DECLARE;
```

Declare the dynamic allocation hooks.

## AUTHOR

Doug Schmidt

## LIBRARY

ace