| blob | e78d18ddff53cecf718cc2a8a8efbf92c0c507b4 |
1 .\" Automatically generated by Pod::Man 2.12 (Pod::Simple 3.05)
2 .\"
3 .\" Standard preamble:
4 .\" ========================================================================
5 .de Sh \" Subsection heading
6 .br
7 .if t .Sp
8 .ne 5
9 .PP
10 \fB\\$1\fR
11 .PP
12 ..
13 .de Sp \" Vertical space (when we can't use .PP)
14 .if t .sp .5v
15 .if n .sp
16 ..
17 .de Vb \" Begin verbatim text
18 .ft CW
19 .nf
20 .ne \\$1
21 ..
22 .de Ve \" End verbatim text
23 .ft R
24 .fi
25 ..
26 .\" Set up some character translations and predefined strings. \*(-- will
27 .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
28 .\" double quote, and \*(R" will give a right double quote. \*(C+ will
29 .\" give a nicer C++. Capital omega is used to do unbreakable dashes and
30 .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
31 .\" nothing in troff, for use with C<>.
32 .tr \(*W-
33 .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
34 .ie n \{\
35 . ds -- \(*W-
36 . ds PI pi
37 . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
38 . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
39 . ds L" ""
40 . ds R" ""
41 . ds C` ""
42 . ds C' ""
43 'br\}
44 .el\{\
45 . ds -- \|\(em\|
46 . ds PI \(*p
47 . ds L" ``
48 . ds R" ''
49 'br\}
50 .\"
51 .\" If the F register is turned on, we'll generate index entries on stderr for
52 .\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index
53 .\" entries marked with X<> in POD. Of course, you'll have to process the
54 .\" output yourself in some meaningful fashion.
55 .if \nF \{\
56 . de IX
57 . tm Index:\\$1\t\\n%\t"\\$2"
58 ..
59 . nr % 0
60 . rr F
61 .\}
62 .\"
63 .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
64 .\" Fear. Run. Save yourself. No user-serviceable parts.
65 . \" fudge factors for nroff and troff
66 .if n \{\
67 . ds #H 0
68 . ds #V .8m
69 . ds #F .3m
70 . ds #[ \f1
71 . ds #] \fP
72 .\}
73 .if t \{\
74 . ds #H ((1u-(\\\\n(.fu%2u))*.13m)
75 . ds #V .6m
76 . ds #F 0
77 . ds #[ \&
78 . ds #] \&
79 .\}
80 . \" simple accents for nroff and troff
81 .if n \{\
82 . ds ' \&
83 . ds ` \&
84 . ds ^ \&
85 . ds , \&
86 . ds ~ ~
87 . ds /
88 .\}
89 .if t \{\
90 . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
91 . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
92 . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
93 . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
94 . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
95 . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
96 .\}
97 . \" troff and (daisy-wheel) nroff accents
98 .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
99 .ds 8 \h'\*(#H'\(*b\h'-\*(#H'
100 .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
101 .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
102 .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
103 .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
104 .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
105 .ds ae a\h'-(\w'a'u*4/10)'e
106 .ds Ae A\h'-(\w'A'u*4/10)'E
107 . \" corrections for vroff
108 .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
109 .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
110 . \" for low resolution devices (crt and lpr)
111 .if \n(.H>23 .if \n(.V>19 \
112 \{\
113 . ds : e
114 . ds 8 ss
115 . ds o a
116 . ds d- d\h'-1'\(ga
117 . ds D- D\h'-1'\(hy
118 . ds th \o'bp'
119 . ds Th \o'LP'
120 . ds ae ae
121 . ds Ae AE
122 .\}
123 .rm #[ #] #H #V #F C
124 .\" ========================================================================
125 .\"
126 .IX Title "BN_CTX_start 3"
127 .TH BN_CTX_start 3 "2007-10-24" "0.9.8g" "OpenSSL"
128 .\" For nroff, turn off justification. Always turn off hyphenation; it makes
129 .\" way too many mistakes in technical documents.
130 .if n .ad l
131 .nh
132 .SH "NAME"
133 BN_CTX_start, BN_CTX_get, BN_CTX_end \- use temporary BIGNUM variables
134 .SH "SYNOPSIS"
135 .IX Header "SYNOPSIS"
136 .Vb 1
137 \& #include <openssl/bn.h>
138 \&
139 \& void BN_CTX_start(BN_CTX *ctx);
140 \&
141 \& BIGNUM *BN_CTX_get(BN_CTX *ctx);
142 \&
143 \& void BN_CTX_end(BN_CTX *ctx);
144 .Ve
145 .SH "DESCRIPTION"
146 .IX Header "DESCRIPTION"
147 These functions are used to obtain temporary \fB\s-1BIGNUM\s0\fR variables from
148 a \fB\s-1BN_CTX\s0\fR (which can been created by using \fIBN_CTX_new\fR\|(3))
149 in order to save the overhead of repeatedly creating and
150 freeing \fB\s-1BIGNUM\s0\fRs in functions that are called from inside a loop.
151 .PP
152 A function must call \fIBN_CTX_start()\fR first. Then, \fIBN_CTX_get()\fR may be
153 called repeatedly to obtain temporary \fB\s-1BIGNUM\s0\fRs. All \fIBN_CTX_get()\fR
154 calls must be made before calling any other functions that use the
155 \&\fBctx\fR as an argument.
156 .PP
157 Finally, \fIBN_CTX_end()\fR must be called before returning from the function.
158 When \fIBN_CTX_end()\fR is called, the \fB\s-1BIGNUM\s0\fR pointers obtained from
159 \&\fIBN_CTX_get()\fR become invalid.
160 .SH "RETURN VALUES"
161 .IX Header "RETURN VALUES"
162 \&\fIBN_CTX_start()\fR and \fIBN_CTX_end()\fR return no values.
163 .PP
164 \&\fIBN_CTX_get()\fR returns a pointer to the \fB\s-1BIGNUM\s0\fR, or \fB\s-1NULL\s0\fR on error.
165 Once \fIBN_CTX_get()\fR has failed, the subsequent calls will return \fB\s-1NULL\s0\fR
166 as well, so it is sufficient to check the return value of the last
167 \&\fIBN_CTX_get()\fR call. In case of an error, an error code is set, which
168 can be obtained by \fIERR_get_error\fR\|(3).
169 .SH "SEE ALSO"
170 .IX Header "SEE ALSO"
171 \&\fIBN_CTX_new\fR\|(3)
172 .SH "HISTORY"
173 .IX Header "HISTORY"
174 \&\fIBN_CTX_start()\fR, \fIBN_CTX_get()\fR and \fIBN_CTX_end()\fR were added in OpenSSL 0.9.5.