1ENVZ_ADD(3)                Library Functions Manual                ENVZ_ADD(3)
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NAME

6       envz_add,  envz_entry,  envz_get, envz_merge, envz_remove, envz_strip -
7       environment string support
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SYNOPSIS

10       #include <envz.h>
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12       error_t
13       envz_add(char **envz, size_t *envz_len,
14                const char *name, const char *value);
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16       char *
17       envz_entry(const char *envz, size_t *envz_len, const char *name);
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19       char *
20       envz_get(const char *envz, size_t *envz_len, const char *name);
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22       error_t
23       envz_merge(char **envz, size_t *envz_len,
24                const char *envz2, size_t envz2_len, int override);
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26       void
27       envz_remove(char **envz, size_t *envz_len, const char *name);
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29       void
30       envz_strip(char **envz, size_t *envz_len);
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DESCRIPTION

34       These functions are glibc-specific.
35
36       An argz vector is a pointer to  a  character  buffer  together  with  a
37       length,  see  argz_add(3).   An  envz  vector is a special argz vector,
38       namely one where the strings have  the  form  "name=value".  Everything
39       after  the first '=' is considered to be the value. If there is no '=',
40       the value is taken to be NULL.  (While the value in case of a  trailing
41       '=' is the empty string "".)
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43       These functions are for handling envz vectors.
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45       envz_add()  adds the string "name=value" (in case value is non-NULL) or
46       "name" (in case value is NULL) to the envz vector (*envz,*envz_len) and
47       updates  *envz  and *envz_len.  If an entry with the same name existed,
48       it is removed.
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50       envz_entry() looks for name in  the  envz  vector  (envz,envz_len)  and
51       returns the entry if found, or NULL if not.
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53       envz_get()  looks  for  name  in  the  envz  vector (envz,envz_len) and
54       returns the value if found, or NULL if not.  (Note that the  value  can
55       also be NULL, namely when there is an entry for name without '=' sign.)
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57       envz_merge()  adds each entry in envz2 to *envz, as if with envz_add().
58       If override is true, then values in envz2 will supersede those with the
59       same name in *envz, otherwise not.
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61       envz_remove()  removes  the  entry  for  name from (*envz,*envz_len) if
62       there was one.
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64       envz_strip() removes all entries with value NULL.
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RETURN VALUE

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

72       #include <stdio.h>
73       #include <envz.h>
74       int
75       main(int argc, char *argv[], char *envp[]) {
76            int i, e_len = 0;
77            char *str;
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79            for (i=0; envp[i] != NULL; i++)
80                 e_len += strlen(envp[i]) + 1;
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82            str = envz_entry(*envp, e_len, "HOME");
83            printf("%s\n", str);
84            str = envz_get(*envp, e_len, "HOME");
85            printf("%s\n", str);
86            return 0;
87       }
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CONFORMING TO

90       These functions are a GNU extension. Handle with care.
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SEE ALSO

93       argz(3)
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97                                                                   ENVZ_ADD(3)
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