1NETSNMP_VARBIND_API(3) Net-SNMP NETSNMP_VARBIND_API(3)
2
6 snmp_pdu_add_variable, snmp_varlist_add_variable, snmp_add_null_var,
7 snmp_clone_varbind, snmp_set_var_objid, snmp_set_var_value,
8 snmp_set_var_typed_value, snmp_set_var_typed_integer, print_variable,
9 fprint_variable, snprint_variable, print_value, fprint_value,
10 snprint_value, snmp_free_var, snmp_free_varbind - netsnmp_varbind_api
11 functions
12
14 #include <net-snmp/varbind_api.h>
15 Creation
17 netsnmp_variable_list *snmp_pdu_add_variable(
18 netsnmp_pdu *pdu,
19 const oid *objid, size_t objidlen,
20 u_char type, const void *value, size_t len);
21 netsnmp_variable_list *snmp_varlist_add_variable(
22 netsnmp_variable_list *varlist,
23 const oid *objid, size_t objidlen,
24 u_char type, const void *value, size_t len);
25 netsnmp_variable_list *snmp_add_null_var(
26 netsnmp_pdu *pdu,
27 const oid *objid, size_t objidlen);
28 netsnmp_variable_list *snmp_clone_varbind(
30 netsnmp_variable_list *varlist);
31 Setting Values
33 int snmp_set_var_objid( netsnmp_variable_list* variable,
34 const oid * objid, size_t objidlen);
35 int snmp_set_var_value( netsnmp_variable_list* variable,
36 const void * value, size_t vallen);
37 int snmp_set_var_typed_value( netsnmp_variable_list* variable,
38 u_char type,
39 const void * value, size_t vallen);
40 int snmp_set_var_typed_integer( netsnmp_variable_list* variable,
41 u_char type, long value);
42 Output
44 void print_variable(const oid *objid, size_t objidlen,
45 const netsnmp_variable_list *variable);
46 void fprint_variable(FILE *fp,
47 const oid *objid, size_t objidlen,
48 const netsnmp_variable_list *variable);
49 int snprint_variable(char *buf, size_t len,
50 const oid *objid, size_t objidlen,
51 const netsnmp_variable_list *variable);
52 void print_value(const oid *objid, size_t objidlen,
54 const netsnmp_variable_list *variable);
55 void fprint_value(FILE *fp,
56 const oid *objid, size_t objidlen,
57 const netsnmp_variable_list *variable);
58 int snprint_value(char *buf, size_t len,
59 const oid *objid, size_t objidlen,
60 const netsnmp_variable_list *variable);
61 Deletion
63 void snmp_free_var( netsnmp_variable_list *variable);
64 void snmp_free_varbind( netsnmp_variable_list *variables);
65
67 The functions dealing with variable bindings fall into four groups -
68 dealing with the creation, setting of values, output and deletion of
69 varbinds.
70 Creation
72 snmp_pdu_add_variable will create a new varbind structure, initialised
73 with the name ( objid, objidlen ), syntax ( type ) and value ( value ,
74 len ) provided. This varbind is then added to the end of the varbind
75 list in the given PDU.
76 snmp_varlist_add_variable is similar, but appends the new varbind to
78 the end of the varbind list provided. When adding the first varbind to
79 an empty list, simply pass the address of the head of the list:
80 netsnmp_variable_list *vl = NULL;
82 snmp_varlist_add_variable(
83 &vl, name1, name1_len,
84 ASN_TYPE, &val1, val1_len);
85 snmp_varlist_add_variable(
86 &vl, name2, name2_len,
87 ASN_TYPE, &val2, val2_len);
88 In both cases, the routine will return a pointer to the new varbind
90 structure (or NULL if the varbind creation fails).
91 snmp_add_null_var is a convenience function to add an empty varbind to
93 the PDU. without needing to specify the NULL value explicitly. This
94 is the normal mechanism for constructing a GET (or similar) information
95 retrieval request.
96 Again, this returns a pointer to the new varbind, or NULL.
97 snmp_clone_varbind creates a copy of each varbind in the specified
99 list, returning a pointer to the head of the new list (or NULL if the
100 cloning fails).
101 Setting of values
103 snmp_set_var_objid sets the name of the varbind structure to the speci‐
104 fied OID.
105 snmp_set_var_typed_value sets the syntax type and value of the varbind
106 structure.
107 snmp_set_var_value sets the value of the varbind structure, leaving the
108 syntax type unchanged.
109 snmp_set_var_typed_integer is a convenience function to set the syntax
110 type and value for a 32-bit integer-based varbind.
111 All four of these return 0 if the assignment is successful, or 1 if it
113 is not.
114 Output
116 print_variable will take an object identifier (as returned by
117 read_objid, snmp_parse_oid or get_module_node) and an instance of such
118 a variable, and prints to the standard output the textual form of the
119 object identifier together with the value of the variable.
120 fprint_variable does the same, but prints to the FILE pointer specified
122 by the initial parameter.
123 snprint_variable prints the same information into the buffer pointed to
125 by buf which is of length len. It returns the number of characters
126 printed, or -1 if the buffer was not large enough. In the latter case,
127 buf will typically contained a truncated version of the information
128 (but this behaviour is not guaranteed). This function replaces the
129 obsolete function sprint_variable.
130 print_value, fprint_value, and snprint_value do the same as the equiva‐
132 lent print_variable routines, but only displaying the value of the
133 variable, without the corresponding object identifier.
134 For displaying the OID of a varbind, see netsnmp_mib_api(3).
136 Deletion
138 snmp_free_var releases all memory used by the given varbind structure.
139 snmp_free_varbind releases all memory used by each varbind structure in
140 the varbind list provided.
141
143 netsnmp_pdu_api(3) netsnmp_mib_api(3)
144V5.8 13 Aug 2010 NETSNMP_VARBIND_API(3)