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ENVZ_ADD(3)			    Linux Programmer's Manual			      ENVZ_ADD(3)

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 3.53 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)
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