• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>
            posts - 297,  comments - 15,  trackbacks - 0

            NAME
                   brk, sbrk - change data segment size

            SYNOPSIS
                   #include <unistd.h>

                   int brk(void *end_data_segment);

                   void *sbrk(intptr_t increment);

            DESCRIPTION
                   brk()  sets the end of the data segment to the value specified by end_data_segment,
                   when that value is reasonable, the system does have enough memory and  the  process
                   does not exceed its max data size (see setrlimit(2)).

                   sbrk() increments the program's data space by increment bytes.  sbrk() isn't a sys-
                   tem call, it is just a C library wrapper.  Calling sbrk() with an  increment  of  0
                   can be used to find the current location of the program break.

            RETURN VALUE
                   On  success,  brk()  returns zero, and sbrk() returns a pointer to the start of the
                   new area.  On error, -1 is returned, and errno is set to ENOMEM.

            CONFORMING TO
                   4.3BSD

                   brk() and sbrk() are not defined in the C Standard and  are  deliberately  excluded
                   from the POSIX.1 standard (see paragraphs B.1.1.1.3 and B.8.3.3).

            NOTES
                   Various  systems  use  various  types for the parameter of sbrk().  Common are int,
                   ssize_t, ptrdiff_t, intptr_t.  XPGv6 obsoletes this function.

            SEE ALSO
                   execve(2), getrlimit(2), malloc(3)

                The brk() and sbrk() functions are used to change the amount of memory
                allocated in a process's data segment. They do this by moving the loca-
                tion of the ``break''. The break is the first address after the end of  
                the process's uninitialized data segment (also known as the ``BSS'').


            brk and sbrk設置的是BSS里的邊界,具體什么是BSS呢
            bss = "Block Started by Symbol" (由符號啟始的區塊)

            Dennis Ritchie 曾說過:
            這個縮寫也許有其它說法,但事實上我們采用這個縮寫的本意是
            "Block Started by Symbol"。它是 FAP 上的偽指令,FAP
            (Fortran Assembly [-er?] Program) 是指 IBM 704-709-7090-7094
            這種機型的組譯器。這個指令可定義自己的標號,并且預留一定數目
            的字組空間。還有另一個偽指令 BES,是 "Block Ended by
            Symbol",跟 BSS 指令幾乎一樣,不同點在于標號是定義在預留字組
            空間尾端的地址 + 1 的地方。在這些機器上,Fortran 的數組是以反
            方向儲存,而且數組的索引是從 1 算起。

            這種用法是合理的,因為這跟 UNIX 上標準的程序加載器一樣,程序
            碼當中并非真的放入這一整塊預留空間,而是先用一個數目表示,在
            加載時才真的把所需的預留空間定出來。
            from:
            Linux man page and
            http://www.linuxforum.net/forum/gshowflat.php?Cat=&Board=linuxK&Number=300677&page=16&view=collapsed&sb=5&o=all&fpart=

            posted on 2010-02-18 19:23 chatler 閱讀(667) 評論(0)  編輯 收藏 引用 所屬分類: Linux_Coding
            <2010年4月>
            28293031123
            45678910
            11121314151617
            18192021222324
            2526272829301
            2345678

            常用鏈接

            留言簿(10)

            隨筆分類(307)

            隨筆檔案(297)

            algorithm

            Books_Free_Online

            C++

            database

            Linux

            Linux shell

            linux socket

            misce

            • cloudward
            • 感覺這個博客還是不錯,雖然做的東西和我不大相關,覺得看看還是有好處的

            network

            OSS

            • Google Android
            • Android is a software stack for mobile devices that includes an operating system, middleware and key applications. This early look at the Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.
            • os161 file list

            overall

            搜索

            •  

            最新評論

            閱讀排行榜

            評論排行榜

            久久午夜福利电影| 久久久国产精华液| 久久久久波多野结衣高潮| 日本精品一区二区久久久| 久久久久久久久久久久中文字幕 | 亚洲伊人久久精品影院| 91精品国产色综合久久| 精品国产综合区久久久久久| 欧美日韩精品久久免费| 精品久久久久久久久久中文字幕| 亚洲精品无码久久久久AV麻豆| 欧美激情精品久久久久| 日韩精品久久久肉伦网站| 亚洲精品成人网久久久久久| 久久精品毛片免费观看| 色8激情欧美成人久久综合电| 久久久久久久亚洲Av无码| 一级女性全黄久久生活片免费| 久久国产色AV免费观看| 久久精品桃花综合| 亚洲欧美久久久久9999| 久久精品无码一区二区三区| 国内精品久久久久伊人av | 久久精品国产精品国产精品污| 久久久久国产| 久久久久99精品成人片三人毛片 | 日韩十八禁一区二区久久 | 国内精品久久久人妻中文字幕| 欧美色综合久久久久久| 激情五月综合综合久久69| 久久精品一区二区三区不卡| 亚洲色欲久久久综合网| 国产色综合久久无码有码| 欧美日韩成人精品久久久免费看| 国产精品永久久久久久久久久| 久久精品成人| 国产毛片久久久久久国产毛片| 久久人人爽爽爽人久久久| 狼狼综合久久久久综合网| 九九久久自然熟的香蕉图片| 国产精品久久久久久吹潮|