{"id":5516,"date":"2022-12-20T18:45:21","date_gmt":"2022-12-20T21:45:21","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/strdup-man3p\/"},"modified":"2022-12-20T18:45:21","modified_gmt":"2022-12-20T21:45:21","slug":"strdup-man3p","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/strdup-man3p\/","title":{"rendered":"STRDUP (man3p)"},"content":{"rendered":"<h1 align=\"center\">STRDUP<\/h1>\n<p> <a href=\"#PROLOG\">PROLOG<\/a><br \/> <a href=\"#NAME\">NAME<\/a><br \/> <a href=\"#SYNOPSIS\">SYNOPSIS<\/a><br \/> <a href=\"#DESCRIPTION\">DESCRIPTION<\/a><br \/> <a href=\"#RETURN VALUE\">RETURN VALUE<\/a><br \/> <a href=\"#ERRORS\">ERRORS<\/a><br \/> <a href=\"#EXAMPLES\">EXAMPLES<\/a><br \/> <a href=\"#APPLICATION USAGE\">APPLICATION USAGE<\/a><br \/> <a href=\"#RATIONALE\">RATIONALE<\/a><br \/> <a href=\"#FUTURE DIRECTIONS\">FUTURE DIRECTIONS<\/a><br \/> <a href=\"#SEE ALSO\">SEE ALSO<\/a><br \/> <a href=\"#COPYRIGHT\">COPYRIGHT<\/a> <\/p>\n<hr>\n<h2>PROLOG <a name=\"PROLOG\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">This manual page is part of the POSIX Programmer\u2019s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.<\/p>\n<h2>NAME <a name=\"NAME\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">strdup, strndup \u2014 duplicate a specific number of bytes from a string<\/p>\n<h2>SYNOPSIS <a name=\"SYNOPSIS\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">#include <string.h><\/p>\n<p style=\"margin-left:11%; margin-top: 1em\">char *strdup(const char *<i>s<\/i>); <br \/> char *strndup(const char *<i>s<\/i>, size_t <i>size<\/i>);<\/p>\n<h2>DESCRIPTION <a name=\"DESCRIPTION\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">The <i>strdup<\/i>() function shall return a pointer to a new string, which is a duplicate of the string pointed to by <i>s<\/i>. The returned pointer can be passed to <i>free<\/i>(). A null pointer is returned if the new string cannot be created.<\/p>\n<p style=\"margin-left:11%; margin-top: 1em\">The <i>strndup<\/i>() function shall be equivalent to the <i>strdup<\/i>() function, duplicating the provided <i>s<\/i> in a new block of memory allocated as if by using <i>malloc<\/i>(), with the exception being that <i>strndup<\/i>() copies at most <i>size<\/i> plus one bytes into the newly allocated memory, terminating the new string with a NUL character. If the length of <i>s<\/i> is larger than <i>size<\/i>, only <i>size<\/i> bytes shall be duplicated. If <i>size<\/i> is larger than the length of <i>s<\/i>, all bytes in <i>s<\/i> shall be copied into the new memory buffer, including the terminating NUL character. The newly created string shall always be properly terminated.<\/p>\n<h2>RETURN VALUE <a name=\"RETURN VALUE\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">The <i>strdup<\/i>() function shall return a pointer to a new string on success. Otherwise, it shall return a null pointer and set <i>errno<\/i> to indicate the error.<\/p>\n<p style=\"margin-left:11%; margin-top: 1em\">Upon successful completion, the <i>strndup<\/i>() function shall return a pointer to the newly allocated memory containing the duplicated string. Otherwise, it shall return a null pointer and set <i>errno<\/i> to indicate the error.<\/p>\n<h2>ERRORS <a name=\"ERRORS\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">These functions shall fail if:<\/p>\n<table width=\"100%\" border=\"0\" rules=\"none\" frame=\"void\" cellspacing=\"0\" cellpadding=\"0\">\n<tr valign=\"top\" align=\"left\">\n<td width=\"11%\"><\/td>\n<td width=\"9%\">\n<p><b>ENOMEM<\/b><\/p>\n<\/td>\n<td width=\"2%\"><\/td>\n<td width=\"61%\">\n<p>Storage space available is insufficient.<\/p>\n<\/td>\n<td width=\"17%\"> <\/td>\n<\/tr>\n<\/table>\n<p style=\"margin-left:11%; margin-top: 1em\"><i>The following sections are informative.<\/i><\/p>\n<h2>EXAMPLES <a name=\"EXAMPLES\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">None.<\/p>\n<h2>APPLICATION USAGE <a name=\"APPLICATION USAGE\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">For functions that allocate memory as if by <i>malloc<\/i>(), the application should release such memory when it is no longer required by a call to <i>free<\/i>(). For <i>strdup<\/i>() and <i>strndup<\/i>(), this is the return value.<\/p>\n<p style=\"margin-left:11%; margin-top: 1em\">Implementations are free to <i>malloc<\/i>() a buffer containing either (<i>size<\/i> + 1) bytes or (<i>strnlen<\/i>( <i>s<\/i>, <i>size<\/i>) + 1) bytes. Applications should not assume that <i>strndup<\/i>() will allocate (<i>size<\/i> + 1) bytes when <i>strlen<\/i>( <i>s<\/i>) is smaller than <i>size<\/i>.<\/p>\n<h2>RATIONALE <a name=\"RATIONALE\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">None.<\/p>\n<h2>FUTURE DIRECTIONS <a name=\"FUTURE DIRECTIONS\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">None.<\/p>\n<h2>SEE ALSO <a name=\"SEE ALSO\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\"><i>free<\/i>(), <i>wcsdup<\/i>()<\/p>\n<p style=\"margin-left:11%; margin-top: 1em\">The Base Definitions volume of POSIX.1-2017, <b><string.h><\/b><\/p>\n<h2>COPYRIGHT <a name=\"COPYRIGHT\"><\/a> <\/h2>\n<p style=\"margin-left:11%; margin-top: 1em\">Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology &#8212; Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http:\/\/www.opengroup.org\/unix\/online.html .<\/p>\n<p style=\"margin-left:11%; margin-top: 1em\">Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https:\/\/www.kernel.org\/doc\/man-pages\/reporting_bugs.html .<\/p>\n<hr>\n","protected":false},"excerpt":{"rendered":"<p>  strdup, strndup \u2014 duplicate a specific number of bytes from a string <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3779,1],"tags":[1594,2402],"class_list":["post-5516","post","type-post","status-publish","format-standard","hentry","category-3pm-perl-llamadas-de-bibliotecas","category-sin-categoria","tag-man3p","tag-strdup"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/5516","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=5516"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/5516\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=5516"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=5516"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=5516"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}