{"id":7158,"date":"2022-12-20T19:35:40","date_gmt":"2022-12-20T22:35:40","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/envz_add-man3\/"},"modified":"2022-12-20T19:35:40","modified_gmt":"2022-12-20T22:35:40","slug":"envz_add-man3","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/envz_add-man3\/","title":{"rendered":"ENVZ_ADD (man3)"},"content":{"rendered":"

ENVZ_ADD<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
RETURN VALUE<\/a>
ATTRIBUTES<\/a>
CONFORMING TO<\/a>
EXAMPLES<\/a>
SEE ALSO<\/a>
COLOPHON<\/a> <\/p>\n

\n

NAME <\/a> <\/h2>\n

envz_add, envz_entry, envz_get, envz_merge, envz_remove, envz_strip \u2212 environment string support<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

#include <\/b><\/p>\n

error_t envz_add(char **<\/b>envz<\/i>, size_t *<\/b>envz_len<\/i>,
const char *<\/b>name<\/i>, const char *<\/b>value<\/i>);<\/b><\/p>\n

char *envz_entry(const char *<\/b>envz<\/i>, size_t<\/b> envz_len<\/i>, const char *<\/b>name<\/i>);<\/b><\/p>\n

char *envz_get(const char *<\/b>envz<\/i>, size_t<\/b> envz_len<\/i>, const char *<\/b>name<\/i>);<\/b><\/p>\n

error_t envz_merge(char **<\/b>envz<\/i>, size_t *<\/b>envz_len<\/i>,
const char *<\/b>envz2<\/i>, size_t<\/b> envz2_len<\/i>, int<\/b> override<\/i>);<\/b><\/p>\n

void envz_remove(char **<\/b>envz<\/i>, size_t *<\/b>envz_len<\/i>, const char *<\/b>name<\/i>);<\/b><\/p>\n

void envz_strip(char **<\/b>envz<\/i>, size_t *<\/b>envz_len<\/i>);<\/b><\/p>\n

DESCRIPTION <\/a> <\/h2>\n

These functions are glibc-specific.<\/p>\n

An argz vector is a pointer to a character buffer together with a length, see argz_add<\/b>(3). An envz vector is a special argz vector, namely one where the strings have the form “name=value”. Everything after the first ‘=’ is considered to be the value. If there is no ‘=’, the value is taken to be NULL. (While the value in case of a trailing ‘=’ is the empty string “”.)<\/p>\n

These functions are for handling envz vectors.<\/p>\n

envz_add<\/b>() adds the string “name<\/i>=value<\/i>” (in case value<\/i> is non-NULL) or “name<\/i>” (in case value<\/i> is NULL) to the envz vector (*envz<\/i>,\u00a0*envz_len<\/i>) and updates *envz<\/i> and *envz_len<\/i>. If an entry with the same name<\/i> existed, it is removed.<\/p>\n

envz_entry<\/b>() looks for name<\/i> in the envz vector (envz<\/i>,\u00a0envz_len<\/i>) and returns the entry if found, or NULL if not.<\/p>\n

envz_get<\/b>() looks for name<\/i> in the envz vector (envz<\/i>,\u00a0envz_len<\/i>) and returns the value if found, or NULL if not. (Note that the value can also be NULL, namely when there is an entry for name<\/i> without ‘=’ sign.)<\/p>\n

envz_merge<\/b>() adds each entry in envz2<\/i> to *envz<\/i>, as if with envz_add<\/b>(). If override<\/i> is true, then values in envz2<\/i> will supersede those with the same name in *envz<\/i>, otherwise not.<\/p>\n

envz_remove<\/b>() removes the entry for name<\/i> from (*envz<\/i>,\u00a0*envz_len<\/i>) if there was one.<\/p>\n

envz_strip<\/b>() removes all entries with value NULL.<\/p>\n

RETURN VALUE <\/a> <\/h2>\n

All envz functions that do memory allocation have a return type of error_t<\/i> (an integer type), and return 0 for success, and ENOMEM<\/b> if an allocation error occurs.<\/p>\n

ATTRIBUTES <\/a> <\/h2>\n

For an explanation of the terms used in this section, see attributes<\/b>(7).<\/p>\n\n\n\n
<\/td>\n <\/td>\n <\/td>\n<\/td>\n<\/td>\n <\/td>\n<\/tr>\n
<\/td>\n<\/td>\n <\/td>\n<\/td>\n<\/td>\n <\/td>\n<\/tr>\n<\/table>\n

\"Image<\/p>\n

CONFORMING TO <\/a> <\/h2>\n

These functions are a GNU extension.<\/p>\n

EXAMPLES <\/a> <\/h2>\n

#include
#include
#include <\/p>\n

int
main(int argc, char *argv[], char *envp[])
{
int e_len = 0;
char *str;<\/p>\n

for (int i = 0; envp[i] != NULL; i++)
e_len += strlen(envp[i]) + 1;<\/p>\n

str = envz_entry(*envp, e_len, “HOME”);
printf(“%sn”, str);
str = envz_get(*envp, e_len, “HOME”);
printf(“%sn”, str);
exit(EXIT_SUCCESS);
}<\/p>\n

SEE ALSO <\/a> <\/h2>\n

argz_add<\/b>(3)<\/p>\n

COLOPHON <\/a> <\/h2>\n

This page is part of release 5.10 of the Linux man-pages<\/i> project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https:\/\/www.kernel.org\/doc\/man\u2212pages\/.<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

envz_add, envz_entry, envz_get, envz_merge, envz_remove, envz_strip \u2212 environment string support <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2536],"tags":[2538,3493,3007],"class_list":["post-7158","post","type-post","status-publish","format-standard","hentry","category-3-llamadas-de-bibliotecas","tag-2538","tag-envz_add","tag-man3"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7158","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=7158"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7158\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=7158"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=7158"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=7158"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}