m_get Kernel Service

Purpose

Allocates a memory buffer (mbuf) from the mbuf pool.

Syntax

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/mbuf.h>

struct mbuf *m_get ( wait,  type)
int wait;
int type;

Parameters

Table 1. Parameters
Item	Description
`wait`	Indicates the action to be taken if there are no free `mbuf` structures. Possible values are: `M_DONTWAIT` Called from either an interrupt or process environment. `M_WAIT` Called from a process environment.
`type`	Specifies a valid `mbuf` type, as listed in the `/usr/include/sys/mbuf.h` file.

Description

The m_get kernel service allocates an mbuf structure of the specified type. If the buffer pool is empty and the wait parameter is set to M_WAIT, the m_get kernel service does not return until an mbuf structure is available.

Execution Environment

The m_get kernel service can be called from either the process or interrupt environment.

An interrupt handler can specify the wait parameter as M_DONTWAIT only.

Return Values

Upon successful completion, the m_get service returns the address of an allocated mbuf structure. If the wait parameter is set to M_DONTWAIT and there are no free mbuf structures, the m_get kernel service returns a null value.