envz_add

ENVZ_ADD(3)							  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.

EXAMPLE
       #include <stdio.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);
	    return 0;
       }

NOTES
       These functions are a GNU extension. Handle with care.

SEE ALSO
       argz(3)



								  ENVZ_ADD(3)