{"id":3404,"date":"2017-07-15T10:38:42","date_gmt":"2017-07-15T02:38:42","guid":{"rendered":"https:\/\/ixyzero.com\/blog\/?p=3404"},"modified":"2017-07-15T10:38:42","modified_gmt":"2017-07-15T02:38:42","slug":"linux%e4%b8%8b%e7%9a%84c%e8%af%ad%e8%a8%80strcpystrncpy%e5%92%8cmemcpy","status":"publish","type":"post","link":"https:\/\/ixyzero.com\/blog\/archives\/3404.html","title":{"rendered":"Linux\u4e0b\u7684C\u8bed\u8a00#strcpy\/strncpy\u548cmemcpy"},"content":{"rendered":"

=Start=<\/p>\n

\u7f18\u7531\uff1a<\/h4>\n

\u6574\u7406\u5b66\u4e60\u5728\u8fdb\u884cLinux\u4e0bC\u7f16\u7a0b\u4e2d\u78b0\u5230\u7684\u4e00\u4e9b\u77e5\u8bc6\u70b9\uff0c\u65b9\u4fbf\u4ee5\u540e\u8fdb\u884c\u53c2\u8003\u3002<\/p>\n

\u6b63\u6587\uff1a<\/h4>\n

\u53c2\u8003\u89e3\u7b54\uff1a<\/h5>\n
\n
\n
\n
\n\n\n\n
\n
\n
void<\/code>\u00a0*memcpy(<\/code>void<\/code>\u00a0*dest,\u00a0<\/code>const<\/code>\u00a0void<\/code>\u00a0*src, size_t n);\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ copies n bytes from memory area src to memory area dest.<\/code><\/div>\n
\/* *\/<\/code><\/div>\n
char<\/code>\u00a0*strcpy(<\/code>char<\/code>\u00a0*dest,\u00a0<\/code>const<\/code>\u00a0char<\/code>\u00a0*src);\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ copies the string pointed to by src, including the terminating null byte ('\\0'), to the buffer pointed to by dest.<\/code><\/div>\n
char<\/code>\u00a0*strncpy(<\/code>char<\/code>\u00a0*dest,\u00a0<\/code>const<\/code>\u00a0char<\/code>\u00a0*src, size_t n);\u00a0\u00a0\u00a0<\/code>\/\/ similar to strcpy(), except that at most n bytes of src are copied<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

&<\/p>\n

\n
\n
\n
\n\n\n\n
\n
\n
int<\/code>\u00a0main()<\/code><\/div>\n
{<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0*t =\u00a0<\/code>\"Working on RedHat Linux\"<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0*s;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>s = malloc (<\/code>8000<\/code>\u00a0* sizeof(<\/code>char<\/code>));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>memcpy(s, t,\u00a0<\/code>7000<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ memcpy(s, t, strlen(t) + 1);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ memcpy(s, t, sizeof(\"Working on RedHat Linux\"));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"s = %s\\nt = %s\\n\"<\/code>, s, t);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>free(s);<\/code><\/div>\n
}<\/code><\/div>\n
\/*<\/code><\/div>\n
\u4ee5\u4e0a\u4ee3\u7801\u51fa\u73b0\u6bb5\u9519\u8bef\u7684\u4e3b\u8981\u539f\u56e0\u5728\u4e8e \u6307\u9488t \u6307\u5411\u7684\u533a\u57df\u5927\u5c0f\u5c0f\u4e8e 7000 \u5b57\u8282\uff0c\u4f46\u662f memcpy() \u8fd8\u662f\u4f1a\u53bb\u8bfb\u53d6 \u6307\u9488t \u6307\u5411\u5b57\u7b26\u4e32\u5185\u5bb9\u4e4b\u540e\u7684\u5185\u5bb9(\u53ef\u80fd\u662f\u4e0d\u53ef\u8bfb\u533a\u57df)\uff0c\u6240\u4ee5\u5f15\u53d1\u6bb5\u9519\u8bef\u3002<\/code><\/div>\n
\u5efa\u8bae\u5728\u4f7f\u7528 memcpy() \u65f6\uff0c\u6e90\u548c\u76ee\u7684\u90fd\u5fc5\u987b\u662f\u53ef\u8bfb\u7684\uff0c\u540c\u65f6\u6700\u597d\u4e5f\u6307\u5b9a\u4e00\u4e2a\u957f\u5ea6\uff0c\u9632\u6b62\u8d8a\u754c\u3002<\/code><\/div>\n
*\/<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

&<\/p>\n

\n
\n
\n
\n\n\n\n
\n
\n
#include <stdio.h><\/code><\/div>\n
#include <string.h><\/code><\/div>\n
<\/div>\n
void<\/code>\u00a0main()<\/code><\/div>\n
{<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0a[<\/code>30<\/code>] =\u00a0<\/code>\"string(1)\"<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>char<\/code>\u00a0b[] =\u00a0<\/code>\"string(2)\"<\/code>;<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"sizeof('%s') = %d\\n\"<\/code>, a, sizeof(a));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"sizeof('%s') = %d\\n\"<\/code>, b, sizeof(b));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"strlen('%s') = %d\\n\"<\/code>, b, strlen(b));<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"before strcpy():%s\\n\"<\/code>, a);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"after strcpy() :%s\\n\"<\/code>, strcpy(a, b));\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ char *strcpy(char *dest,const char *src);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ a[30] = \"string(1)\";\u00a0\u00a0\u00a0 \/\/warning: assignment makes integer from pointer without a cast<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>strcpy(a,\u00a0<\/code>\"string(1)\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"after strncpy(a, b, 6) :%s\\n\"<\/code>, strncpy(a, b,\u00a0<\/code>6<\/code>));\u00a0\u00a0\u00a0\u00a0<\/code>\/\/ char *strncpy(char *dest,const char *src,size_t n);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>strcpy(a,\u00a0<\/code>\"string(1)\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"after strncpy(a, b, sizeof(b)) :%s\\n\"<\/code>, strncpy(a, b, sizeof(b)));<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>strcpy(a,\u00a0<\/code>\"string(1)\"<\/code>);<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>printf(<\/code>\"after strncpy(a, b, strlen(b)+1) :%s\\n\"<\/code>, strncpy(a, b, strlen(b)+<\/code>1<\/code>));<\/code><\/div>\n
}<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
\u53c2\u8003\u94fe\u63a5\uff1a<\/h5>\n

http:\/\/man7.org\/linux\/man-pages\/man3\/memcpy.3.html<\/a><\/p>\n

C\u51fd\u6570\u4e4bmemcpy()\u51fd\u6570\u7528\u6cd5
\nhttp:\/\/blog.csdn.net\/tigerjibo\/article\/details\/6841531<\/a><\/p>\n

memcpy\u6ee5\u7528\u5bfc\u81f4\u7684\u300csegmentation fault\u300d<\/strong>
\nhttps:\/\/stackoverflow.com\/questions\/8703948\/memcpy-function-in-c<\/a><\/p>\n

\u5b57\u7b26\u4e32\u62f7\u8d1d\/\u8d4b\u503c \u9664\u4e86\u5728\u521d\u59cb\u5316\u7684\u65f6\u5019\u76f4\u63a5\u8d4b\u503c\u5916\uff0c\u5728\u540e\u671f\u5904\u7406\u4e0a\u9700\u8981\u4f7f\u7528 strcpy\/strncpy \u800c\u4e0d\u80fd\u76f4\u63a5\u7528 = \u8d4b\u503c<\/span><\/strong>
\nhttp:\/\/www.iteedu.com\/os\/linux\/linuxprgm\/linuxcfunctions\/memstring\/strncpy.php<\/a><\/p>\n

http:\/\/man7.org\/linux\/man-pages\/man3\/strcpy.3.html<\/a>
\nhttps:\/\/linux.die.net\/man\/3\/strcpy<\/a><\/p>\n

\u4e3a\u4ec0\u4e48\u8be5\u4f7f\u7528 strncpy \u800c\u4e0d\u662f strcpy
\nhttps:\/\/stackoverflow.com\/questions\/1258550\/why-should-you-use-strncpy-instead-of-strcpy<\/a><\/p>\n

=END=<\/p>\n","protected":false},"excerpt":{"rendered":"

=Start= \u7f18\u7531\uff1a \u6574\u7406\u5b66\u4e60\u5728\u8fdb\u884cLinux\u4e0bC\u7f16\u7a0b\u4e2d\u78b0\u5230\u7684\u4e00\u4e9b\u77e5\u8bc6\u70b9\uff0c\u65b9\u4fbf\u4ee5\u540e\u8fdb\u884c\u53c2\u8003\u3002 \u6b63\u6587\uff1a \u53c2\u8003\u89e3 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23,11,7],"tags":[100,30,851,850],"class_list":["post-3404","post","type-post","status-publish","format-standard","hentry","category-knowledgebase-2","category-linux","category-programing","tag-c","tag-linux","tag-memcpy","tag-strcpy"],"views":3389,"_links":{"self":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/3404","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/comments?post=3404"}],"version-history":[{"count":2,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/3404\/revisions"}],"predecessor-version":[{"id":3420,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/posts\/3404\/revisions\/3420"}],"wp:attachment":[{"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/media?parent=3404"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/categories?post=3404"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ixyzero.com\/blog\/wp-json\/wp\/v2\/tags?post=3404"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}