NAME

       envz_add, envz_entry, envz_get, envz_merge, envz_remove, envz_strip - environment string support

SYNOPSIS

       #include <envz.h>

       error_t envz_add(char **envz, size_t *envz_len,
                        const char *name, const char *value);

       char *envz_entry(const char *envz, size_t *envz_len, const char *name);

       char *envz_get(const char *envz, size_t *envz_len, const char *name);

       error_t envz_merge(char **envz, size_t *envz_len,
                          const char *envz2, size_t envz2_len, int override);

       void envz_remove(char **envz, size_t *envz_len, const char *name);

       void envz_strip(char **envz, size_t *envz_len);

DESCRIPTION

       These functions are glibc-specific.

       An  argz  vector  is  a  pointer  to a character buffer together with a length, see argz_add(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 "".)

       These functions are for handling envz vectors.

       envz_add() adds the string "name=value" (in case value is non-NULL) or "name" (in case value is NULL)  to
       the  envz  vector  (*envz, *envz_len)  and  updates  *envz and *envz_len.  If an entry with the same name
       existed, it is removed.

       envz_entry() looks for name in the envz vector (envz, envz_len) and returns the entry if found,  or  NULL
       if not.

       envz_get()  looks for name in the envz vector (envz, envz_len) 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 without '=' sign.)

       envz_merge() adds each entry in envz2 to *envz, as if with envz_add().  If override is true, then  values
       in envz2 will supersede those with the same name in *envz, otherwise not.

       envz_remove() removes the entry for name from (*envz, *envz_len) if there was one.

       envz_strip() removes all entries with value NULL.

RETURN VALUE

       All envz functions that do memory allocation have a return type of error_t, and return 0 for success, and
       ENOMEM if an allocation error occurs.

CONFORMING TO

       These functions are a GNU extension.  Handle with care.

EXAMPLE

       #include <stdio.h>
       #include <stdlib.h>
       #include <envz.h>

       int
       main(int argc, char *argv[], char *envp[])
       {
           int i, e_len = 0;
           char *str;

           for (i = 0; envp[i] != NULL; i++)
               e_len += strlen(envp[i]) + 1;

           str = envz_entry(*envp, e_len, "HOME");
           printf("%s\n", str);
           str = envz_get(*envp, e_len, "HOME");
           printf("%s\n", str);
           exit(EXIT_SUCCESS);
       }

SEE ALSO

       argz_add(3)

COLOPHON

       This page is part of release 3.54 of the Linux man-pages project.  A  description  of  the  project,  and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

                                                   2007-05-18                                        ENVZ_ADD(3)