---
name: "ACE_RW_Process_Mutex"
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_RW_Process_Mutex"
---

# ACE\_RW\_Process\_Mutex(3)

Wrapper for readers/writer locks that exist across processes.

## NAME

ACE\_RW\_Process\_Mutex -  Wrapper for readers/writer locks that exist across processes.

## SYNOPSIS

```
#include <ace/Synch.h>
class ACE_RW_Process_Mutex
{
  public:
    ACE_RW_Process_Mutex (
        LPCTSTR name = 0,
        int flags = O_CREAT|O_RDWR
        );
    ~ACE_RW_Process_Mutex (void);
    int remove (void);
    int acquire (void);
    int tryacquire (void);
    int release (void);
    int acquire_read (void);
    int acquire_write (void);
    int tryacquire_read (void);
    int tryacquire_write (void);
    const ACE_File_Lock &lock (void) const;
    void dump (void) const;
    ACE_ALLOC_HOOK_DECLARE;
  private:
    ACE_File_Lock lock_;
};
```

## DESCRIPTION

Wrappers for various synchronization routines.

## PUBLIC MEMBERS

```
ACE_RW_Process_Mutex (LPCTSTR name = 0, int flags = O_CREAT|O_RDWR);
```

Create a readers/writer Process\_Mutex, passing in the optional name.

```
~ACE_RW_Process_Mutex (void);
```

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

Explicitly destroy the mutex.  Note that only one thread should call this method since it doesn't protect against race conditions.

```
int acquire (void);
```

Acquire lock ownership (wait on queue if necessary).

```
int tryacquire (void);
```

Conditionally acquire lock (i.e., don't wait on queue).  Returns -1 on failure.  If we "failed" because someone else already had the lock, errno is set to EBUSY.

```
int release (void);
```

Release lock and unblock a thread at head of queue.

```
int acquire_read (void);
```

Acquire lock ownership (wait on queue if necessary).

```
int acquire_write (void);
```

Acquire lock ownership (wait on queue if necessary).

```
int tryacquire_read (void);
```

Conditionally acquire a lock (i.e., won't block).  Returns -1 on failure.  If we "failed" because someone else already had the lock, errno is set to EBUSY.

```
int tryacquire_write (void);
```

Conditionally acquire a lock (i.e., won't block).  Returns -1 on failure.  If we "failed" because someone else already had the lock, errno is set to EBUSY.

```
const ACE_File_Lock &lock (void) const;
```

Return the underlying lock.

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

Dump the state of an object.

```
ACE_ALLOC_HOOK_DECLARE;
```

Declare the dynamic allocation hooks.

## PRIVATE MEMBERS

```
ACE_File_Lock lock_;
```

We need this to get the readers/writer semantics...

## AUTHOR

Doug Schmidt

## LIBRARY

ace