{"id":140,"date":"2022-10-03T13:53:44","date_gmt":"2022-10-03T13:53:44","guid":{"rendered":"http:\/\/example.com\/?p=132"},"modified":"2022-10-03T13:53:44","modified_gmt":"2022-10-03T13:53:44","slug":"132-mmap-read","status":"publish","type":"post","link":"https:\/\/w2.geleleger.nl\/rhcuk-132-mmap-read-esknvp\/","title":{"rendered":"Mmap Read"},"content":{"rendered":"<div class=\"387480d42754320bb6f0e83bf7886d44\" data-index=\"1\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script type=\"text\/javascript\">\r\n\tatOptions = {\r\n\t\t'key' : '4a1f1119f949a4af74d56b8a3af8b867',\r\n\t\t'format' : 'iframe',\r\n\t\t'height' : 250,\r\n\t\t'width' : 300,\r\n\t\t'params' : {}\r\n\t};\r\n\tdocument.write('<scr' + 'ipt type=\"text\/javascript\" src=\"http' + (location.protocol === 'https:' ? 's' : '') + ':\/\/bleedingofficecontagion.com\/4a1f1119f949a4af74d56b8a3af8b867\/invoke.js\"><\/scr' + 'ipt>');\r\n<\/script>\n<\/div>\n\n<p><strong>Mmap Read<\/strong>. <strong>I&#39;m trying to read a file to a string using mmap. The address space of the process from the address returned to the caller, for a length of len, is mapped onto a stream file starting at offset. off. A memory-mapped file is created by the mmap constructor, which is different on Unix and on Windows. The mmap() function establishes a mapping between a process&#39; address space. and a stream file. Description. mmap_read opens filename for reading, maps the whole file into memory, closes the file, writes the length of the file to filesize and returns a pointer to the mapped file. An efficient implementation of mmap () is actually only possible from a practical perspective because of paging and virtual memory (otherwise, it would require reading the whole region into memory before the call completes). You can also read and write data starting at the current file position, and seek () through the file to different positions. The file is unmapped by the operating system if the process terminates.<\/strong><\/p>\n<p><figure> \t\t<img decoding=\"async\" src=\"https:\/\/s2.51cto.com\/images\/blog\/202206\/09021525_62a0e73da976247305.png?x-oss-process=image\/watermark,size_16,text_QDUxQ1RP5Y2a5a6i,color_FFFFFF,t_30,g_se,x_10,y_10,shadow_20,type_ZmFuZ3poZW5naGVpdGk=\/resize,m_fixed,w_1184\" alt=\"\u3010\u52a8\u753b\u56fe\u6587\u6df1\u5ea6\u8be6\u89e3\u3011\u5185\u5b58\u6620\u5c04\u6587\u4ef6 mmap \u539f\u7406\u6df1\u5ea6\u5256\u6790_51CTO\u535a\u5ba2_linux\u5185\u5b58\u6620\u5c04mmap\u539f\u7406\u5206\u6790\" style=\"width: 100%; padding: 5px; background-color: grey;\"><figcaption>\u3010\u52a8\u753b\u56fe\u6587\u6df1\u5ea6\u8be6\u89e3\u3011\u5185\u5b58\u6620\u5c04\u6587\u4ef6 mmap \u539f\u7406\u6df1\u5ea6\u5256\u6790_51CTO\u535a\u5ba2_linux\u5185\u5b58\u6620\u5c04mmap\u539f\u7406\u5206\u6790 (Kenneth Dennis)<\/figcaption><\/figure>\n<p> \t \t<strong>Mmap Read<\/strong>. <strong>In either case you must provide a file descriptor for a file opened for update. The format of the call is as follows: pa=mmap (addr, len, prot, flags, fildes, off); The file to read. The file is unmapped by the operating system if the process terminates. I use mmap, read and write system calls to copy file. NAME top. mmap, munmap &#8211; map or unmap files or devices into memory.<\/strong> Mmap Read. <\/p>\n<h3>Description. mmap_read opens filename for reading, maps the whole file into memory, closes the file, writes the length of the file to filesize and returns a pointer to the mapped file.<\/h3>\n<p>However, the result is that regardless of the block size, mmap is always slower than read and write.<\/p>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/jesse505.github.io\/img\/201906\/mmap.jpg\"><img decoding=\"async\" src=\"https:\/\/jesse505.github.io\/img\/201906\/mmap.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse4.mm.bing.net\/th?id=OIP.edltvKLPbATkbPM3YVNjZgHaD2&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Android\u9ad8\u6027\u80fd\u65e5\u5fd7\u5199\u5165\u65b9\u6848-mmap | \u8d75\u4e00\u98de\u7684\u535a\u5ba2<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"http:\/\/www.valleyareaaging.org\/wp-content\/uploads\/2015\/07\/mmap-logo-2013.jpg\"><img decoding=\"async\" src=\"http:\/\/www.valleyareaaging.org\/wp-content\/uploads\/2015\/07\/mmap-logo-2013.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse1.mm.bing.net\/th?id=OIP.ZNkT_OABJhB_ubeJ3i062QHaHa&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Medicare\/Medicaid Assistance (MMAP)<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/image.slidesharecdn.com\/mmap-160426081701\/95\/linux-mmap-ioremap-introduction-24-638.jpg?cb=1461658652\"><img decoding=\"async\" src=\"https:\/\/image.slidesharecdn.com\/mmap-160426081701\/95\/linux-mmap-ioremap-introduction-24-638.jpg?cb=1461658652\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.Rrf9hxhq_app3Sy-jrqEcwHaFj&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Linux MMAP &amp; Ioremap introduction<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/img-blog.csdnimg.cn\/20190201161432283.png?x-oss-process=image\/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21jcnllYXN5,size_16,color_FFFFFF,t_70\"><img decoding=\"async\" src=\"https:\/\/img-blog.csdnimg.cn\/20190201161432283.png?x-oss-process=image\/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L21jcnllYXN5,size_16,color_FFFFFF,t_70\" onerror=\"this.onerror=null;this.src='https:\/\/tse1.mm.bing.net\/th?id=OIP.TvbKNqebzuImIy5a3s_soQHaFS&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Android-\u5185\u5b58\u6620\u5c04mmap_mcryeasy\u7684\u535a\u5ba2-CSDN\u535a\u5ba2_android mmap<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"http:\/\/wiki.dreamrunner.org\/public_html\/C-C++\/Library-Notes\/Files\/mmap-linux.gif\"><img decoding=\"async\" src=\"http:\/\/wiki.dreamrunner.org\/public_html\/C-C++\/Library-Notes\/Files\/mmap-linux.gif\" onerror=\"this.onerror=null;this.src='https:\/\/tse1.mm.bing.net\/th?id=OIP.WPMLlJxy3j8xulMODp6OwgHaFU&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>LMDB\u4e2d\u7684mmap\u3001Copy On Write\u3001MVCC\u6df1\u5165\u7406\u89e3\u2014\u2014\u8bb2\u5f97\u975e\u5e38\u597d\uff0c\u5e38\u6765\u770b\u770b!_weixin_33701294\u7684\u535a\u5ba2-CSDN\u535a\u5ba2<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/swsmile.info\/post\/assets\/image-20190304124439034.png\"><img decoding=\"async\" src=\"https:\/\/swsmile.info\/post\/assets\/image-20190304124439034.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse3.mm.bing.net\/th?id=OIP.nOf_RWbusAuXzemSBi6qTwHaFL&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>\u3010Operating System\u3011I\/O &#8211; \u96f6\u62f7\u8d1d\uff08Zero-copy\uff09-\u897f\u7ef4\u8700\u9ecd\u7684\u535a\u5ba2 | \u897f\u7ef4\u8700\u9ecd Blog<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/i.stack.imgur.com\/erSUc.png\"><img decoding=\"async\" src=\"https:\/\/i.stack.imgur.com\/erSUc.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.IVUihU8Wb3taU3zPpkHJIgHaGE&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>c &#8211; how does a program runs in memory and the way memory is handled by &#8230;<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/miro.medium.com\/v2\/resize:fit:527\/1*5zz42fTTNfioTySnTWweOg.png\"><img decoding=\"async\" src=\"https:\/\/miro.medium.com\/v2\/resize:fit:527\/1*5zz42fTTNfioTySnTWweOg.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse4.mm.bing.net\/th?id=OIP.69ZgAlogJBRZDDVO0yqdsQHaLz&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>MMap&#39;s in Python. yes you read it correct its 2 M&#39;s | by Nishanth G &#8230;<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/pic3.zhimg.com\/v2-302ff3afccdff6841f18b5eadd437c76_r.jpg\"><img decoding=\"async\" src=\"https:\/\/pic3.zhimg.com\/v2-302ff3afccdff6841f18b5eadd437c76_r.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.KHolvplhpSfqKtuT2_EhGAHaC5&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>Linux\u4e2d\u7684mmap\u6620\u5c04 [\u4e00] &#8211; \u77e5\u4e4e<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<div style=\"display: grid;grid-template-columns: auto auto auto; background: #eee; \">\n<div style=\"padding: 1em;\"> \t\t        <a href=\"http:\/\/static.oschina.net\/uploads\/space\/2011\/0930\/232658_vw4l_117227.png\"><img decoding=\"async\" src=\"http:\/\/static.oschina.net\/uploads\/space\/2011\/0930\/232658_vw4l_117227.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse1.mm.bing.net\/th?id=OIP.POwYnbb4Tw5ViOTF5S4plwHaED&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>[\u8f6c]mmap\u8be6\u89e3 &#8211; Orion<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/kuafu1994.github.io\/MoreOnMemory\/assets\/mmap_write.png\"><img decoding=\"async\" src=\"https:\/\/kuafu1994.github.io\/MoreOnMemory\/assets\/mmap_write.png\" onerror=\"this.onerror=null;this.src='https:\/\/tse2.mm.bing.net\/th?id=OIP.1vjTV6AuXQhDoq-X_ggv2AHaBm&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>mmap \u00b7 GitBook<\/p>\n<\/p><\/div>\n<div style=\"padding: 1em;\"> \t\t        <a href=\"https:\/\/i.ytimg.com\/vi\/grgBiVCzIIw\/maxresdefault.jpg\"><img decoding=\"async\" src=\"https:\/\/i.ytimg.com\/vi\/grgBiVCzIIw\/maxresdefault.jpg\" onerror=\"this.onerror=null;this.src='https:\/\/tse1.mm.bing.net\/th?id=OIP.m4JJ0ENpHzoB6nt3xS72XwHaEK&amp;pid=Api';\" style=\"width:100%;margin-top: 8px;vertical-align: middle;\"><\/a> \t\t        <\/p>\n<p>C++ : Read a file line by line with mmap &#8211; YouTube<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<p><strong>Mmap Read<\/strong>. <strong>Here&#39;s an example of reading the system dictionary file by memory-mapping it. If I try to iterate over the object I get character instead of complete lines. Physical Memory: It is the random access memory (RAM) and is a volatile memory. Performance Implications. mmap Object Creation. mmap Objects as Strings. These apps are known to open certain types of MMAP files.<\/p>\n<p><\/strong> Mmap Read.<\/p>\n<div class=\"387480d42754320bb6f0e83bf7886d44\" data-index=\"2\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script type=\"text\/javascript\">\r\n\tatOptions = {\r\n\t\t'key' : '4a1f1119f949a4af74d56b8a3af8b867',\r\n\t\t'format' : 'iframe',\r\n\t\t'height' : 250,\r\n\t\t'width' : 300,\r\n\t\t'params' : {}\r\n\t};\r\n\tdocument.write('<scr' + 'ipt type=\"text\/javascript\" src=\"http' + (location.protocol === 'https:' ? 's' : '') + ':\/\/bleedingofficecontagion.com\/4a1f1119f949a4af74d56b8a3af8b867\/invoke.js\"><\/scr' + 'ipt>');\r\n<\/script>\n<\/div>\n\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>Mmap Read. I&#39;m trying to read a file to a string using mmap. The address space of the process from the address returned to the caller, for a length of len, is mapped onto a stream file starting at offset. off. A memory-mapped file is created by the mmap constructor, which is different on Unix&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/posts\/140"}],"collection":[{"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/comments?post=140"}],"version-history":[{"count":0,"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/posts\/140\/revisions"}],"wp:attachment":[{"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/media?parent=140"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/categories?post=140"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/w2.geleleger.nl\/wp-json\/wp\/v2\/tags?post=140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}