pr_attachsharedmemory.md

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# PR_AttachSharedMemory

Attaches a memory segment previously opened with {ref}`PR_OpenSharedMemory`

and maps it into the process memory space.

## Syntax

```{code}

#include <prshm.h>

```

```{code}

NSPR_API( void * )

  PR_AttachSharedMemory(

     PRSharedMemory *shm,

     PRIntn flags

);

/* Define values for PR_AttachSharedMemory(...,flags) */

#define PR_SHM_READONLY 0x01

```

### Parameters

The function has these parameters:

shm

: The handle returned from {ref}`PR_OpenSharedMemory`.

flags

: Options for mapping the shared memory. `PR_SHM_READONLY` causes the

  memory to be attached read-only.

### Returns

Address where shared memory is mapped, or `NULL` if an error occurs.

Retrieve the reason for the failure by calling {ref}`PR_GetError` and

{ref}`PR_GetOSError`.