---
name: "ACE_SV_Shared_Memory"
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_SV_Shared_Memory"
---

# ACE\_SV\_Shared\_Memory(3)

This is a wrapper for System V shared memory.

## NAME

ACE\_SV\_Shared\_Memory -  This is a wrapper for System V shared memory.

## SYNOPSIS

```
#include <ace/SV_Shared_Memory.h>
class ACE_SV_Shared_Memory
{
  public:
    enum{ ACE_CREATE = IPC_CREAT, ACE_OPEN = 0 };
    ACE_SV_Shared_Memory (void);
    ACE_SV_Shared_Memory (
        key_t external_id,
        size_t size,
        int create,
        int perms = ACE_DEFAULT_FILE_PERMS,
        void *virtual_addr = 0,
        int flags = 0
        );
    ACE_SV_Shared_Memory (ACE_HANDLE internal_id, int flags = 0);
    int open (
        key_t external_id,
        size_t size,
        int create = ACE_SV_Shared_Memory::ACE_OPEN,
        int perms = ACE_DEFAULT_FILE_PERMS
        );
    int open_and_attach (
        key_t external_id,
        size_t size,
        int create = ACE_SV_Shared_Memory::ACE_OPEN,
        int perms = ACE_DEFAULT_FILE_PERMS,
        void *virtual_addr = 0,
        int flags = 0
        );
    int attach (void *virtual_addr = 0, int flags =0);
    int detach (void);
    int remove (void);
    int control (int cmd, void *buf);
    void *get_segment_ptr (void) const;
    int get_segment_size (void) const;
    ACE_HANDLE get_id (void) const;
    void dump (void) const;
    ACE_ALLOC_HOOK_DECLARE;
  protected:
    enum{ ALIGN_WORDB = 8 };
    ACE_HANDLE internal_id_;
    int size_;
    void *segment_ptr_;
    int round_up (size_t len);
};
```

## Initialization and termination methods.

```
ACE_SV_Shared_Memory (void);
```

```
ACE_SV_Shared_Memory (
    key_t external_id,
    size_t size,
    int create,
    int perms = ACE_DEFAULT_FILE_PERMS,
    void *virtual_addr = 0,
    int flags = 0
    );
```

```
ACE_SV_Shared_Memory (ACE_HANDLE internal_id, int flags = 0);
```

```
int open (
    key_t external_id,
    size_t size,
    int create = ACE_SV_Shared_Memory::ACE_OPEN,
    int perms = ACE_DEFAULT_FILE_PERMS
    );
```

```
int open_and_attach (
    key_t external_id,
    size_t size,
    int create = ACE_SV_Shared_Memory::ACE_OPEN,
    int perms = ACE_DEFAULT_FILE_PERMS,
    void *virtual_addr = 0,
    int flags = 0
    );
```

```
int attach (void *virtual_addr = 0, int flags =0);
```

Attach this shared memory segment.

```
int detach (void);
```

Detach this shared memory segment.

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

Remove this shared memory segment.

```
int control (int cmd, void *buf);
```

Forward to underlying System V shmctl.

## Segment-related info.

```
void *get_segment_ptr (void) const;
```

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

```
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