envz_strip(3) -- Linux man page
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)
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