December 2013
Intermediate to advanced
496 pages
8h 57m
Chinese
Content preview from LINUX系統程式設計 第二版
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記憶體管理
|
335
XPG 標準所定義的
mallopt()
多了三個參數：
M_GRAIN
、
M_KEEP
以及
M_NLBLKS
。儘管
Linux 也有定義這些參數，但是設定它們的值毫無作用。表 9-1 完整地列出了每個有效
的參數、它們的預定值以及它們的可用值範圍。
表 9-1 mallopt() 參數
參數 起源 預定值 有效值 特殊值
M_CHECK_ACTION
Linux 特有 0
0 ― 2
M_GRAIN
XPG 標準 Linux 不支援
M_KEEP
XPG 標準 Linux 不支援
M_MMAP_MAX
Linux 特有 64 * 1024
>=0
0 禁用
mmap()
M_MMAP_THRESHOLD
Linux 特有 128 * 1024
>=0
0 禁用堆積
M_MXFAST
XPG 標準 64
0-80
0 禁止 fast bin
M_NLBLKS
XPG 標準 Linux 不支援
M_PERTURB
Linux 特有 0
0
或
1
0 禁止污染記憶體
M_TOP_PAD
Linux 特有 0
>= 0
0 禁止頂部補白
M_TRIM_THRESHOLD
Linux 特有 128 * 1024
>=-1
-1 禁止修剪
程式在首次叫用
malloc()
或任何其他記憶體分配介面之前，必須先對
mallopt()
進行調
用。它的用法很簡單：
int ret;
/* 把 mmap() 用在超過 64 KB 的所有分配需求 */
ret = mallopt (M_MMAP_THRESHOLD, 64 * 1024);
if (!ret)
fprintf ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.