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fea681da | 1 | .\" Copyright 2002 walter harms (walter.harms@informatik.uni-oldenburg.de) |
2297bf0e | 2 | .\" |
38f20bb9 | 3 | .\" %%%LICENSE_START(GPL_NOVERSION_ONELINE) |
fea681da | 4 | .\" Distributed under GPL |
38f20bb9 | 5 | .\" %%%LICENSE_END |
0389adc9 | 6 | .\" |
fea681da | 7 | .\" based on the description in glibc source and infopages |
c13182ef | 8 | .\" |
fea681da | 9 | .\" Corrections and additions, aeb |
4b8c67d9 | 10 | .TH ENVZ_ADD 3 2017-09-15 "" "Linux Programmer's Manual" |
fea681da MK |
11 | .SH NAME |
12 | envz_add, envz_entry, envz_get, envz_merge, | |
13 | envz_remove, envz_strip \- environment string support | |
14 | .SH SYNOPSIS | |
15 | .nf | |
fea681da | 16 | .B "#include <envz.h>" |
dbfe9c70 | 17 | .PP |
e7c0f078 | 18 | .BI "error_t envz_add(char **" envz ", size_t *" envz_len , |
dcf163b9 | 19 | .BI " const char *" name ", const char *" value ); |
dbfe9c70 | 20 | .PP |
5c1d7bca | 21 | .BI "char *envz_entry(const char *" envz ", size_t " envz_len \ |
e7c0f078 | 22 | ", const char *" name ); |
dbfe9c70 | 23 | .PP |
5c1d7bca | 24 | .BI "char *envz_get(const char *" envz ", size_t " envz_len \ |
e7c0f078 | 25 | ", const char *" name ); |
dbfe9c70 | 26 | .PP |
e7c0f078 | 27 | .BI "error_t envz_merge(char **" envz ", size_t *" envz_len , |
dcf163b9 MK |
28 | .BI " const char *" envz2 ", size_t " envz2_len \ |
29 | ", int " override ); | |
dbfe9c70 | 30 | .PP |
e7c0f078 MK |
31 | .BI "void envz_remove(char **" envz ", size_t *" envz_len \ |
32 | ", const char *" name ); | |
dbfe9c70 | 33 | .PP |
e7c0f078 | 34 | .BI "void envz_strip(char **" envz ", size_t *" envz_len ); |
c8250206 | 35 | .fi |
fea681da | 36 | .SH DESCRIPTION |
8382f16d | 37 | These functions are glibc-specific. |
dd3568a1 | 38 | .PP |
fea681da MK |
39 | An argz vector is a pointer to a character buffer together with a length, |
40 | see | |
41 | .BR argz_add (3). | |
42 | An envz vector is a special argz vector, namely one where the strings | |
c13182ef | 43 | have the form "name=value". |
f81fb444 | 44 | Everything after the first \(aq=\(aq is considered |
c13182ef | 45 | to be the value. |
f81fb444 MK |
46 | If there is no \(aq=\(aq, the value is taken to be NULL. |
47 | (While the value in case of a trailing \(aq=\(aq is the empty string "".) | |
dd3568a1 | 48 | .PP |
fea681da | 49 | These functions are for handling envz vectors. |
dd3568a1 | 50 | .PP |
63aa9df0 | 51 | .BR envz_add () |
fea681da MK |
52 | adds the string |
53 | .RI \&" name = value \&" | |
54 | (in case | |
55 | .I value | |
56 | is non-NULL) or | |
57 | .RI \&" name \&" | |
58 | (in case | |
59 | .I value | |
60 | is NULL) to the envz vector | |
e7c0f078 | 61 | .RI ( *envz ,\ *envz_len ) |
fea681da | 62 | and updates |
e7c0f078 | 63 | .I *envz |
fea681da | 64 | and |
e7c0f078 | 65 | .IR *envz_len . |
fea681da MK |
66 | If an entry with the same |
67 | .I name | |
68 | existed, it is removed. | |
dd3568a1 | 69 | .PP |
63aa9df0 | 70 | .BR envz_entry () |
fea681da MK |
71 | looks for |
72 | .I name | |
73 | in the envz vector | |
e7c0f078 | 74 | .RI ( envz ,\ envz_len ) |
fea681da | 75 | and returns the entry if found, or NULL if not. |
dd3568a1 | 76 | .PP |
63aa9df0 | 77 | .BR envz_get () |
fea681da MK |
78 | looks for |
79 | .I name | |
80 | in the envz vector | |
e7c0f078 | 81 | .RI ( envz ,\ envz_len ) |
fea681da MK |
82 | and returns the value if found, or NULL if not. |
83 | (Note that the value can also be NULL, namely when there is | |
84 | an entry for | |
85 | .I name | |
f81fb444 | 86 | without \(aq=\(aq sign.) |
dd3568a1 | 87 | .PP |
63aa9df0 | 88 | .BR envz_merge () |
fea681da MK |
89 | adds each entry in |
90 | .I envz2 | |
91 | to | |
e7c0f078 | 92 | .IR *envz , |
fea681da | 93 | as if with |
63aa9df0 | 94 | .BR envz_add (). |
fea681da MK |
95 | If |
96 | .I override | |
97 | is true, then values in | |
98 | .I envz2 | |
99 | will supersede those with the same name in | |
e7c0f078 | 100 | .IR *envz , |
fea681da | 101 | otherwise not. |
dd3568a1 | 102 | .PP |
63aa9df0 | 103 | .BR envz_remove () |
fea681da MK |
104 | removes the entry for |
105 | .I name | |
106 | from | |
e7c0f078 | 107 | .RI ( *envz ,\ *envz_len ) |
fea681da | 108 | if there was one. |
dd3568a1 | 109 | .PP |
e511ffb6 | 110 | .BR envz_strip () |
fea681da | 111 | removes all entries with value NULL. |
47297adb | 112 | .SH RETURN VALUE |
fea681da | 113 | All envz functions that do memory allocation have a return type of |
c6fa0841 MK |
114 | .IR error_t , |
115 | and return 0 for success, and | |
116 | .B ENOMEM | |
fea681da | 117 | if an allocation error occurs. |
29a663f7 MS |
118 | .SH ATTRIBUTES |
119 | For an explanation of the terms used in this section, see | |
120 | .BR attributes (7). | |
121 | .TS | |
122 | allbox; | |
123 | lbw27 lb lb | |
124 | l l l. | |
125 | Interface Attribute Value | |
126 | T{ | |
127 | .BR envz_add (), | |
128 | .BR envz_entry (), | |
129 | .br | |
130 | .BR envz_get (), | |
131 | .BR envz_merge (), | |
132 | .br | |
133 | .BR envz_remove (), | |
134 | .BR envz_strip () | |
135 | T} Thread safety MT-Safe | |
136 | .TE | |
847e0d88 | 137 | .sp 1 |
47297adb | 138 | .SH CONFORMING TO |
2b2581ee MK |
139 | These functions are a GNU extension. |
140 | Handle with care. | |
fea681da | 141 | .SH EXAMPLE |
207050fa | 142 | .EX |
fea681da | 143 | #include <stdio.h> |
af9c7ff2 | 144 | #include <stdlib.h> |
fea681da | 145 | #include <envz.h> |
cf0a9ace | 146 | |
fea681da | 147 | int |
cf0a9ace MK |
148 | main(int argc, char *argv[], char *envp[]) |
149 | { | |
150 | int i, e_len = 0; | |
151 | char *str; | |
fea681da | 152 | |
22a33e86 | 153 | for (i = 0; envp[i] != NULL; i++) |
cf0a9ace | 154 | e_len += strlen(envp[i]) + 1; |
fea681da | 155 | |
cf0a9ace | 156 | str = envz_entry(*envp, e_len, "HOME"); |
31a6818e | 157 | printf("%s\en", str); |
cf0a9ace | 158 | str = envz_get(*envp, e_len, "HOME"); |
31a6818e | 159 | printf("%s\en", str); |
5bc8c34c | 160 | exit(EXIT_SUCCESS); |
fea681da | 161 | } |
207050fa | 162 | .EE |
47297adb | 163 | .SH SEE ALSO |
d122bd56 | 164 | .BR argz_add (3) |