{"id":55262,"date":"2025-08-13T20:14:48","date_gmt":"2025-08-13T12:14:48","guid":{"rendered":"https:\/\/www.wsisp.com\/helps\/55262.html"},"modified":"2025-08-13T20:14:48","modified_gmt":"2025-08-13T12:14:48","slug":"%e5%ad%a6%e4%b9%a0%e5%b5%8c%e5%85%a5%e5%bc%8f%e7%9a%84%e7%ac%ac%e5%8d%81%e4%b9%9d%e5%a4%a9-linux-%e6%96%87%e4%bb%b6%e7%bc%96%e7%a8%8b","status":"publish","type":"post","link":"https:\/\/www.wsisp.com\/helps\/55262.html","title":{"rendered":"\u5b66\u4e60\u5d4c\u5165\u5f0f\u7684\u7b2c\u5341\u4e5d\u5929\u2014\u2014Linux\u2014\u2014\u6587\u4ef6\u7f16\u7a0b"},"content":{"rendered":"

\"\"<\/h2>\n

\u6807\u51c6IO<\/h2>\n

\u8fdb\u4e00\u6b65\u8ba4\u8bc6\u6807\u51c6io:\u00a0<\/h3>\n

\n\u00a0 \u00a0 1975 Dennis r IO\u5e93，
\n\u00a0 \u00a0 \u4eceC\u8bed\u8a00\u7684\u6807\u51c6，ANSI c\u00a0
\n\u00a0\u00a0 \u00a0IO \u00a0input \u00a0output
\n\u00a0\u00a0 \u00a0I： \u952e\u76d8\u662f\u6807\u51c6\u8f93\u5165\u8bbe\u5907 ====\u300b\u9ed8\u8ba4\u8f93\u5165\u5c31\u662f\u6307\u952e\u76d8 \u00a0\/dev\/input
\n\u00a0\u00a0 \u00a0O： \u663e\u793a\u5668\u662f\u6807\u51c6\u8f93\u51fa\u8bbe\u5907 ==\u300b\u9ed8\u8ba4\u8f93\u51fa\u5c31\u662f\u6307\u663e\u793a\u5668<\/p>\n

Linux\u64cd\u4f5c\u7cfb\u7edf\u5f53\u4e2dIO\u90fd\u662f\u5bf9\u6587\u4ef6\u7684\u64cd\u4f5c
\n\u00a0\u00a0 \u00a0C\u4e00\u90e8\u5206，\u4efb\u4f55\u652f\u6301\u6807\u51c6C\u7684\u7cfb\u7edf\u90fd\u53ef\u4f7f\u7528\u6807\u51c6IO\u5b9e\u73b0\u6587\u4ef6\u5b58\u50a8
\n\u00a0\u00a0 \u00a0\u6807\u51c6IO\u5728UNIX\u4e0a\u662f\u5bf9\u6587\u4ef6IO\u7684\u5c01\u88c5<\/p>\n

\u4e00\u822c\u90fd\u662f\u5bf9\u666e\u901a\u6587\u4ef6\u64cd\u4f5c\u662f\u4e00\u79cd\u6709\u7f13\u5b58\u7684IO \u5728\u6587\u4ef6IO\u548c\u7528\u6237\u7a0b\u5e8f\u4e4b\u95f4，
\n\u00a0\u00a0 \u00a0\u52a0\u5165\u7f13\u51b2\u533a，\u53ef\u4ee5\u6709\u6548\u51cf\u5c11\u7cfb\u7edf\u8c03\u7528\u7684\u6b21\u6570，\u8282\u7701\u7cfb\u7edfIO\u8c03\u5ea6\u8d44\u6e90<\/p>\n

\u8bf4\u660e:
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u6807\u51c6IO\u5e93，\u4e0d\u5355\u5355\u662flinux\u4e0a\u6709，\u5728windows，Mac os\u4e0a\u90fd\u6709\u3002
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u5f88\u591a\u64cd\u4f5c\u7cfb\u7edf\u90fd\u5b9e\u73b0\u4e86\u6807\u51c6IO\u5e93\u3002
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u90fd\u662f\u4f9d\u636eIOS C\u6807\u51c6\u5b9e\u73b0\u7684\u3002
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u6240\u4ee5\u57fa\u672c\u4fdd\u8bc1\u4e86\u53ef\u79fb\u690d\u6027\u3002
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u4f46\u662f\u56e0\u4e3a\u6807\u51c6\u548c\u5177\u4f53\u5b9e\u73b0\u4e4b\u95f4\u7684\u5dee\u5f02，
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u672a\u5fc5\u6562\u4fdd\u8bc1\u6240\u6709\u7684\u51fd\u6570\u5728\u90fd\u53ef\u4ee5\u76f8\u4e92\u901a\u7528\u3002<\/p>\n

\u6807\u51c6IO\u90fd\u5e72\u4e86\u4e9b\u5565？<\/h3>\n

\n\u00a0\u00a0 \u00a0\u6807\u51c6IO\u5904\u7406\u4e86\u5f88\u591a\u7ec6\u8282:
\n\u00a0\u00a0 \u00a0(1).\u5904\u7406\u7f13\u51b2\u533a\u5206\u914d \u00a0 （\u7f13\u5b58–\u63d0\u9ad8\u6548\u7387 — \u6162\u901f \u5feb\u901f）
\n\u00a0\u00a0 \u00a0(2).\u8bfb\u5199IO\u7684\u5757\u957f\u5ea6\u7684\u4f18\u5316
\n\u00a0\u00a0 \u00a0(3).\u5bf9\u7cfb\u7edf\u8c03\u7528\u8fdb\u884c\u4e86\u5c01\u88c5，\u5185\u90e8\u5bf9\u5e94\u7684"\u6587\u4ef6\u63cf\u8ff0\u7b26"<\/p>\n

\u597d\u5904:
\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0\u7528\u6237\u4f7f\u7528\u65b9\u4fbf，\u4e0d\u5fc5\u518d\u62c5\u5fc3\u5982\u4f55\u9009\u62e9\u6b63\u786e\u7684\u5757\u957f\u5ea6<\/p>\n

\u5730\u4f4d:
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u6807\u51c6I\/O\u5e93\u662f\u7531Dennis Ritchie\u57281975\u5e74\u5de6\u53f3\u7f16\u5199\u7684\u3002
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u5b83\u662fMike Lesk\u7f16\u5199\u7684\u53ef\u79fb\u690dI\/O\u5e93\u7684\u4e3b\u8981\u4fee\u6539\u7248\u672c\u3002
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u4ee4\u4eba\u60ca\u8bb6\u7684\u662f，35\u5e74\u6765，\u51e0\u4e4e\u6ca1\u6709\u5bf9\u6807\u51c6I\/O\u5e93\u8fdb\u884c\u4fee\u6539\u3002<\/p>\n

\u5b9a\u4f4d\u51fd\u6570\u00a0 \u00a0fseek()\u00a0 \u00a0\u00a0ftell()\u00a0\u00a0rewind()<\/h3>\n

int fseek(FILE *stream, long offset, int whence);
\n\u00a0 \u00a0 \u00a0 \u00a0\u529f\u80fd:
\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u5c06stream\u6307\u5b9a\u7684\u6587\u4ef6，\u4ecewhence\u4f4d\u7f6e，\u5b9a\u4f4d\u5230offset\u7684\u4f4d\u7f6e\u00a0
\n\u00a0\u00a0 \u00a0 \u00a0 \u53c2\u6570:
\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0@stream \u00a0 — \u8868\u793a\u8981\u5b9a\u4f4d\u7684\u6587\u4ef6\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0@offset \u00a0 — \u504f\u79fb\u91cf\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0>0 \u00a0 \/\/\u9700\u8981\u8003\u8651\u53c2\u8003\u70b9\u662f\u5426\u53ef\u4ee5\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0<0\u00a0 \u00a0\/\/\u53ef\u4ee5\u5c0f\u4e8e0，\u4e5f\u9700\u8981\u770b\u53c2\u8003\u70b9
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0@whence \u00a0 — \u53c2\u8003\u70b9\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0SEEK_SET \u00a0\/\/\u6587\u4ef6\u5f00\u5934\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0SEEK_CUR \u00a0\/\/\u6587\u4ef6\u5f53\u524d\u4f4d\u7f6e\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0SEEK_END \u00a0\/\/\u6587\u4ef6\u7ed3\u5c3e
\n\u00a0 \u00a0 \u00a0 \u8fd4\u56de\u503c:
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u6210\u529f \u00a0 0\u00a0
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u5931\u8d25 -1 && errno\u4f1a\u88ab\u8bbe\u7f6e<\/p>\n

fseek(fp,0,SEEK_SET); \/\/\u5b9a\u4f4d\u5230\u5f00\u5934\u00a0
\nfseek(fp,0,SEEK_END); \/\/\u5b9a\u4f4d\u5230\u5f00\u5934 \u00a0\u00a0
\nfseek(fp,100,SEEK_SET);\/\/\u4ece\u5934\u5f80\u540e \u504f\u79fb 100\u4e2a\u5b57\u8282 \u00a0\u00a0
\nfseek(fp,-100,SEEK_SET);\/\/\u4ece\u5934\u5f80\u540e \u504f\u79fb 100\u4e2a\u5b57\u8282<\/p>\n

\u8bf4\u660e:
\n\u00a0 \u00a0 \u00a0 \u6587\u4ef6\u5f80\u540e\u504f\u79fb\u91cf \u5982\u679c\u5927\u4e8e \u6587\u4ef6\u672c\u8eab\u662f\u53ef\u4ee5\u7684\u00a0
\n\u00a0 \u00a0 \u00a0 \u5982\u679c\u60f3\u5360\u6709\u5b58\u50a8\u7a7a\u95f4，\u5fc5\u987b\u8981\u6709\u5199\u64cd\u4f5c\u00a0<\/p>\n

\u00a0 \u00a0 \u00a0 \u591a\u51fa\u6765\u7684\u7a7a\u95f4 — \u7a7a\u6d1e — \u7528'\\\\0'<\/p>\n

long ftell(FILE *stream);
\n\u00a0\u00a0 \u00a0 \u00a0 \u83b7\u5f97stream\u5bf9\u5e94\u6587\u4ef6\u7684\u5f53\u524d\u4f4d\u7f6e\u6307\u793a\u5668\u7684\u503c\u00a0
\n\u00a0\u00a0 \u00a0 \u00a0 eg:
\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0 \/\/\u6587\u4ef6\u5927\u5c0f\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 fseek(fp,0,SEEK_END);
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0 long len = ftell(fp);<\/p>\n

void rewind(FILE *stream);
\n\u00a0 \u00a0 \u00a0 \u00a0\u529f\u80fd，\u5c06\u6587\u4ef6\u5b9a\u4f4d\u5230\u5f00\u5934<\/p>\n

\u7a7a\u6d1e\u6587\u4ef6<\/h4>\n

\u521b\u5efa\u7a7a\u6d1e\u6587\u4ef6\u6b65\u9aa4:
\n\u00a0\u00a0 \u00a0 \u00a01.\u5b9a\u4f4d \u504f\u79fb\u00a0
\n\u00a0\u00a0 \u00a0 \u00a02.\u505a\u4e00\u6b21\u5199\u64cd\u4f5c<\/p>\n

\u5982\u767e\u5ea6\u4e91\u4e4b\u7c7b\u7684，\u4ece\u4e0a\u9762\u4e0b\u8f7d\u6587\u4ef6\u90fd\u4f1a\u5148\u521b\u5efa\u7a7a\u6d1e\u6587\u4ef6\u63d0\u524d\u62a2\u5360\u78c1\u76d8\u7a7a\u95f4，\u5982\u679c\u7a7a\u95f4\u4e0d\u8db3\u53ef\u4ee5\u63d0\u524d\u63d0\u9192，\u51cf\u5c11\u65f6\u95f4\u7684\u635f\u8017<\/p>\n

\u7f13\u5b58\u533a<\/h2>\n

\u7f13\u5b58\u7684\u8bbe\u8ba1\u539f\u5219:
\n1.\u4e0e\u7ec8\u7aef\u5173\u8054\u7684\u8bbe\u5907 \u00a0 —\u884c\u7f13\u5b58\u00a0
\n2.\u666e\u901a\u6587\u4ef6 \u00a0 \u00a0 \u00a0 \u00a0 —\u5168\u7f13\u5b58\u00a0
\n3.\u51fa\u9519\u5904\u7406 \u00a0 \u00a0 \u00a0 \u00a0 —\u4e0d\u7f13\u5b58\u00a0<\/p>\n

\u884c\u7f13\u51b2<\/h3>\n

1k， terminal，\u4e3b\u8981\u7528\u4e8e\u4eba\u673a\u4ea4\u4e92stdout，\u591a\u7528\u4e8e\u4e0e\u5ba2\u6237\u6709\u4e92\u52a8<\/p>\n

\u884c\u7f13\u5b58\u591a\u662f\u5173\u4e8e\u7ec8\u7aef\u7684\u4e00\u4e9b\u64cd\u4f5c<\/p>\n

\u5237\u65b0\u6761\u4ef6：<\/p>\n

1.\u9047\u5230\\\\n\u5237\u65b0
\n2.\u7f13\u5b58\u533a\u6ee1\u5237\u65b0
\n3.\u7a0b\u5e8f\u6b63\u5e38\u7ed3\u675f\u5237\u65b0
\n4.fflush\u5237\u65b0 \u00a0fflush(stdout);<\/p>\n

\u5168\u7f13\u51b2<\/h3>\n

4k，\u4e3b\u8981\u7528\u4e8e\u6587\u4ef6\u7684\u8bfb\u5199<\/p>\n

\u5bf9\u666e\u901a\u6587\u4ef6\u8fdb\u884c\u6807\u51c6IO\u64cd\u4f5c，\u5efa\u7acb\u7684\u7f13\u5b58\u4e00\u822c\u4e3a\u5168\u7f13\u5b58<\/p>\n

\u5237\u65b0\u6761\u4ef6:
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a01.\u7f13\u5b58\u533a\u6ee1\u5237\u65b0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a02.\u7a0b\u5e8f\u7ed3\u675f\u5237\u65b0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a03.fflush\u6765\u5237\u65b0 \u00a0fflush(fp);<\/p>\n

\u8f93\u51fa\u91cd\u5b9a\u5411<\/h4>\n

.\/a.out\u00a0\u00a0 \u00a0> 1.txt \/\/\u628aa.out\u8fd0\u884c\u7684\u7ed3\u679c\u8f93\u51fa\u52301.txt\u4e2d<\/p>\n

\u65e0\u7f13\u51b2<\/h3>\n

0k \u00a0\u4e3b\u8981\u7528\u4e8e\u51fa\u9519\u5904\u7406\u4fe1\u606f\u7684\u8f93\u51fa stderr\u00a0
\n\u00a0\u00a0 \u00a0\u4e0d\u5bf9\u6570\u636e\u7f13\u5b58\u76f4\u63a5\u5237\u65b0<\/p>\n

\u6807\u51c6IO\u5c0f\u7ed3<\/h2>\n

\"\"<\/p>\n

\u5e93\u51fd\u6570\u548c\u7cfb\u7edf\u8c03\u7528
\n\u00a0 \u00a01. \u5e93\u51fd\u6570\u6700\u7ec8\u8fd8\u662f\u501f\u52a9\u7cfb\u7edf\u8c03\u7528\u6765\u5b9e\u73b0\u00a0
\n\u00a0 \u00a0\u5e93\u51fd\u6570
\n\u00a0 \u00a0 \u4f18\u70b9:
\n\u00a0\u00a0 \u00a0 \u00a0\u66f4\u4e30\u5bcc\u7684\u529f\u80fd\u00a0
\n\u00a0\u00a0 \u00a0 \u00a0\u66f4\u4f18\u5316\u7684\u5904\u7406
\n\u00a0 \u00a0 \u00a0 \u65b9\u4fbf\u9ad8\u6548 \u00a0\u00a0 \u00a0 \u00a0
\n\u00a0\u00a0 \u00a0\u7f3a\u70b9:
\n\u00a0\u00a0 \u00a0 \u00a0\u5b89\u5168\u6027 \u00a0
\n\u00a0 \u00a0 \u00a0\u00a0
\n\u00a0 \u00a0\u7cfb\u7edf\u8c03\u7528
\n\u00a0 \u00a0 \u4f18\u70b9:
\n\u00a0\u00a0 \u00a0 \u7b80\u5355\u00a0
\n\u00a0\u00a0 \u00a0 \u5b89\u5168\u6027\u00a0
\n\u00a0\u00a0 \u00a0\u7f3a\u70b9:
\n\u00a0\u00a0 \u00a0 \u529f\u80fd\u4e0d\u591f\u4e30\u5bcc\u00a0
\n\u00a0\u00a0 \u00a0 \u4f7f\u7528\u8d77\u6765\u4e0d\u5927\u65b9\u4fbf\u00a0<\/p>\n

\u6587\u4ef6IO<\/h2>\n

open<\/h3>\n

#include <fcntl.h><\/p>\n

int open(const char *pathname, int flags);
\nint open(const char *pathname, int flags, mode_t mode);\u00a0\u00a0 \u00a0<\/p>\n

\u529f\u80fd:
\n\u00a0 \u00a0\u6253\u5f00\u6587\u4ef6\u00a0
\n\u53c2\u6570:
\n\u00a0 @pathname — \u6587\u4ef6\u540d\u00a0
\n\u00a0 @flags\u00a0
\n\u00a0 \u00a0 \u00a0 \u00a0 \u5fc5\u9009:
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0O_RDONLY
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0O_WRONLY
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0O_RDWR
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u9644\u52a0:
\n\u00a0\u00a0 \u00a0 \u00a0 \u00a0O_APPEND \/\/\u8ffd\u52a0 —\u5199\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0O_CREAT \u00a0\/\/\u521b\u5efa\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0O_TRUNC \u00a0\/\/\u622a\u65ad\u00a0
\n\u00a0 @mode
\n\u00a0 \u00a0 \u00a0 \u00a0\u8868\u793a\u521b\u5efa\u6587\u4ef6\u7684\u6743\u9650 — \u53ea\u6709\u524d\u9762\u6709O_CREAT\u65f6，\u624d\u9700\u8981\u6307\u5b9a\u00a0
\n\u00a0\u00a0 \u00a0 \u00a0 0777
\n\u00a0\u00a0 \u00a0 \u00a0 0666<\/p>\n

\u5b9e\u9645\u7684\u6587\u4ef6\u6743\u9650:<\/p>\n

mode & ~umask<\/p>\n

\"\"
\n\u8fd4\u56de\u503c:
\n\u00a0 \u00a0\u6210\u529f \u8fd4\u56de\u6587\u4ef6\u63cf\u8ff0\u7b26\u00a0
\n\u00a0 \u00a0\u5931\u8d25 -1 &&errno\u00a0<\/p>\n

\u4e0efopen\u7684\u5173\u7cfb<\/p>\n

\"\"<\/p>\n

close<\/h3>\n

close（\u6587\u4ef6\u63cf\u8ff0\u7b26）<\/p>\n

\u5173\u95ed\u4e00\u4e2a\u6587\u4ef6，\u5e76\u4e14\u4f7f\u8be5\u6587\u4ef6\u63cf\u8ff0\u7b26\u53ef\u4ee5\u91cd\u590d\u4f7f\u7528<\/p>\n

read<\/h3>\n

ssize_t read(int fd, void *buf, size_t count);
\n\u529f\u80fd:
\n\u00a0 \u00a0 \u4ecefd\u5bf9\u5e94\u6587\u4ef6\u4e2d\u8bfb\u53d6\u6570\u636e，\u8bfbcount\u4e2a\u5b57\u8282，\u5b58\u653e\u5230buf\u6307\u5b9a\u7684\u4e00\u5757\u7a7a\u95f4\u00a0
\n\u53c2\u6570:
\n\u00a0 @fd \u00a0 \u00a0\u5c31\u662f\u8981\u8bfb\u53d6\u7684\u6587\u4ef6\u00a0
\n\u00a0 @buf \u00a0 \u5b58\u653e\u6570\u636e\u7684\u7a7a\u95f4\u00a0
\n\u00a0 @count \u8981\u8bfb\u53d6\u7684\u5b57\u8282\u6570
\n\u8fd4\u56de\u503c;
\n\u00a0 \u00a0\u6210\u529f \u8bfb\u53d6\u5230\u7684\u5b57\u8282\u6570\u00a0
\n\u00a0 \u00a0\u5931\u8d25 -1 &&errno\u00a0<\/p>\n

\u6ce8\u610f:
\n\u00a0 \u00a0read\u8bfb\u5230\u7684\u6570\u636e，\u5982\u679c\u8981\u5f53\u4f5c\u5b57\u7b26\u4e32\u5904\u7406，
\n\u00a0 \u00a0\u6ce8\u610f，\u9700\u8981\u624b\u52a8\u5904\u7406\u6210\u5b57\u7b26\u4e32 ，\u5373\u624b\u52a8\u52a0'\\\\0'<\/p>\n

write<\/h3>\n

ssize_t write(int fd, const void *buf, size_t count);
\n\u00a0\u529f\u80fd:
\n\u00a0 \u00a0 \u4ecebuf\u4e2d\u83b7\u5f97\u6570\u636e，\u5199count\u4e2a\u5b57\u8282\u5230 fd\u5bf9\u5e94\u6587\u4ef6\u4e2d
\n\u53c2\u6570:
\n\u00a0 @fd \u00a0 \u00a0\u5c31\u662f\u8981\u5199\u7684\u6587\u4ef6\u00a0
\n\u00a0 @buf \u00a0 \u5b58\u653e\u6570\u636e\u7684\u7a7a\u95f4\u00a0
\n\u00a0 @count \u8981\u5199\u5165\u7684\u5b57\u8282\u6570
\n\u8fd4\u56de\u503c;
\n\u00a0 \u00a0\u6210\u529f \u5199\u5165\u7684\u5b57\u8282\u6570\u00a0
\n\u00a0 \u00a0\u5931\u8d25 -1 &&errno \u00a0<\/p>\n

lseek<\/h3>\n

lseek<\/p>\n

off_t lseek(int fd, off_t offset, int whence);
\n\u529f\u80fd:
\n\u00a0 \u00a0 \u00a0\u5c06fd\u5b9a\u4f4d\u5230\u4ecewhence\u5f00\u59cb\u7684offset\u7684\u4f4d\u7f6e\u00a0
\n\u53c2\u6570:
\n\u00a0 \u00a0 @fd \u6587\u4ef6\u00a0
\n\u00a0 \u00a0 @offset \u504f\u79fb\u91cf\u00a0
\n\u00a0\u00a0 \u00a0@offset \u00a0 — \u504f\u79fb\u91cf\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0>0 \u00a0 \/\/\u9700\u8981\u8003\u8651\u53c2\u8003\u70b9\u662f\u5426\u53ef\u4ee5\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0<0\u00a0
\n\u00a0\u00a0 \u00a0@whence \u00a0 — \u53c2\u8003\u70b9\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0SEEK_SET \u00a0\/\/\u6587\u4ef6\u5f00\u5934\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0SEEK_CUR \u00a0\/\/\u6587\u4ef6\u5f53\u524d\u4f4d\u7f6e\u00a0
\n\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0SEEK_END \u00a0\/\/\u6587\u4ef6\u7ed3\u5c3e<\/p>\n

\u5b9a\u4f4d\u5f00\u5934:
\n\u00a0 \u00a0lseek(fd,0,SEEK_SET);
\n\u5b9a\u4f4d\u5230\u672b\u5c3e
\n\u00a0 \u00a0lseek(fd,0,SEEK_END);
\n\u00a0 \u00a0
\n\u8fd4\u56de\u503c:
\n\u00a0 \u00a0\u6210\u529f \u8fd4\u56de\u4ece\u6587\u5e93\u5f00\u5934\u5230\u5f53\u524d\u5b9a\u4f4d\u5904\u7684\u504f\u79fb\u91cf\u00a0
\n\u00a0 \u00a0\u5931\u8d25 -1 && errno<\/p>\n

\/\/\u83b7\u5f97\u6587\u4ef6\u5927\u5c0f\u00a0
\n\u00a0off_t len = lseek(fd,0,SEEK_END);\u00a0 \u00a0 \u00a0 \/\/off_t \u662f\u4e00\u4e2along int\u578b\u00a0<\/p>\n

\u6d41\u6307\u9488\u4e0e\u6587\u4ef6\u63cf\u8ff0\u7b26\u7684\u8f6c\u6362<\/h2>\n

int fileno(FILE *stream); \/\/\u5c06FILE *fp \u6d41\u6307\u9488\u8f6c\u6362\u4e3a fd\u00a0
\n\u00a0 \u00a0fd —> FILE *fp\u00a0<\/p>\n

FILE *fdopen(int fd, const char *mode);<\/p>\n

\u529f\u80fd:
\n\u5c06 fd \u5bf9\u5e94\u6587\u4ef6\u6253\u5f00 \u5173\u8054\u4e00\u4e2a FILE * \u6307\u9488\u00a0<\/p><\/p>\n","protected":false},"excerpt":{"rendered":"

\u6587\u7ae0\u6d4f\u89c8\u9605\u8bfb113\u6b21\u3002\u5982\u767e\u5ea6\u4e91\u4e4b\u7c7b\u7684\uff0c\u4ece\u4e0a\u9762\u4e0b\u8f7d\u6587\u4ef6\u90fd\u4f1a\u5148\u521b\u5efa\u7a7a\u6d1e\u6587\u4ef6\u63d0\u524d\u62a2\u5360\u78c1\u76d8\u7a7a\u95f4\uff0c\u5982\u679c\u7a7a\u95f4\u4e0d\u8db3\u53ef\u4ee5\u63d0\u524d\u63d0\u9192\uff0c\u51cf\u5c11\u65f6\u95f4\u7684\u635f\u8017\u3002I\uff1a \u952e\u76d8\u662f\u6807\u51c6\u8f93\u5165\u8bbe\u5907 ====\u300b\u9ed8\u8ba4\u8f93\u5165\u5c31\u662f\u6307\u952e\u76d8 \/dev\/input\u3002.\/a.out > 1.txt \/\/\u628aa.out\u8fd0\u884c\u7684\u7ed3\u679c\u8f93\u51fa\u52301.txt\u4e2d\u3002\u8868\u793a\u521b\u5efa\u6587\u4ef6\u7684\u6743\u9650 — \u53ea\u6709\u524d\u9762\u6709O_CREAT\u65f6\uff0c\u624d\u9700\u8981\u6307\u5b9a\u3002<0 \/\/\u53ef\u4ee5\u5c0f\u4e8e0\uff0c\u4e5f\u9700\u8981\u770b\u53c2\u8003\u70b9\u3002SEEK_CUR \/\/\u6587\u4ef6\u5f53\u524d\u4f4d\u7f6e\u3002SEEK_SET \/\/\u6587\u4ef6\u5f00\u5934\u3002<\/p>\n","protected":false},"author":2,"featured_media":55258,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[371],"topic":[],"class_list":["post-55262","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-371"],"yoast_head":"\n\u5b66\u4e60\u5d4c\u5165\u5f0f\u7684\u7b2c\u5341\u4e5d\u5929\u2014\u2014Linux\u2014\u2014\u6587\u4ef6\u7f16\u7a0b - 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