NAME
envz_add, envz_entry, envz_get, envz_merge,
envz_remove, envz_strip - environment string support
SYNOPSIS
#include <envz.h>
I error_t
I envz_add(char ** envz , size_t * envz_len ,
I const char * name , const char * value );
I char *
I envz_entry(const char * envz , size_t * envz_len , const char * name );
I char *
I envz_get(const char * envz , size_t * envz_len , const char * name );
I error_t
I envz_merge(char ** envz , size_t * envz_len ,
I const char * envz2 , size_t envz2_len , int override );
I void
I envz_remove(char ** envz , size_t * envz_len , const char * name );
I void
I 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.
R 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.
R envz_entry ()
looks for
name
in the envz vector
(envz,envz_len)
and returns the entry if found, or NULL if not.
R 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.)
R envz_merge ()
adds each entry in
envz2
to
*envz,
as if with
R envz_add ().
If
override
is true, then values in
envz2
will supersede those with the same name in
*envz,
otherwise not.
R envz_remove ()
removes the entry for
name
from
(*envz,*envz_len)
if there was one.
R 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 <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
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