xref: /freebsd/secure/lib/libcrypto/man/man3/BN_CTX_new.3 (revision 5def4c47d4bd90b209b9b4a4ba9faec15846d8fd)
Automatically generated by Pod::Man 4.14 (Pod::Simple 3.42)

Standard preamble:
========================================================================
..
..
.. Set up some character translations and predefined strings. \*(-- will
give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
double quote, and \*(R" will give a right double quote. \*(C+ will
give a nicer C++. Capital omega is used to do unbreakable dashes and
therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
nothing in troff, for use with C<>.
.tr \(*W- . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\}
Escape single quotes in literal strings from groff's Unicode transform.

If the F register is >0, we'll generate index entries on stderr for
titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
entries marked with X<> in POD. Of course, you'll have to process the
output yourself in some meaningful fashion.

Avoid warning from groff about undefined register 'F'.
.. .nr rF 0 . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF
Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
Fear. Run. Save yourself. No user-serviceable parts.
. \" fudge factors for nroff and troff . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] .\} . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents . \" corrections for vroff . \" for low resolution devices (crt and lpr) \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} ========================================================================

Title "BN_CTX_NEW 3"
BN_CTX_NEW 3 "2021-03-25" "1.1.1k" "OpenSSL"
For nroff, turn off justification. Always turn off hyphenation; it makes
way too many mistakes in technical documents.
"NAME"
BN_CTX_new, BN_CTX_secure_new, BN_CTX_free - allocate and free BN_CTX structures
"SYNOPSIS"
Header "SYNOPSIS" .Vb 1 #include <openssl/bn.h> \& BN_CTX *BN_CTX_new(void); \& BN_CTX *BN_CTX_secure_new(void); \& void BN_CTX_free(BN_CTX *c); .Ve
"DESCRIPTION"
Header "DESCRIPTION" A \s-1BN_CTX\s0 is a structure that holds \s-1BIGNUM\s0 temporary variables used by library functions. Since dynamic memory allocation to create \s-1BIGNUM\s0s is rather expensive when used in conjunction with repeated subroutine calls, the \s-1BN_CTX\s0 structure is used.

\fBBN_CTX_new() allocates and initializes a \s-1BN_CTX\s0 structure. \fBBN_CTX_secure_new() allocates and initializes a \s-1BN_CTX\s0 structure but uses the secure heap (see CRYPTO_secure_malloc\|(3)) to hold the \fB\s-1BIGNUM\s0s.

\fBBN_CTX_free() frees the components of the \s-1BN_CTX\s0 and the structure itself. Since BN_CTX_start() is required in order to obtain \s-1BIGNUM\s0s from the \fB\s-1BN_CTX\s0, in most cases BN_CTX_end() must be called before the \s-1BN_CTX\s0 may be freed by BN_CTX_free(). If c is \s-1NULL,\s0 nothing is done.

A given \s-1BN_CTX\s0 must only be used by a single thread of execution. No locking is performed, and the internal pool allocator will not properly handle multiple threads of execution.

"RETURN VALUES"
Header "RETURN VALUES" \fBBN_CTX_new() and BN_CTX_secure_new() return a pointer to the \s-1BN_CTX\s0. If the allocation fails, they return \s-1NULL\s0 and sets an error code that can be obtained by \fBERR_get_error\|(3).

\fBBN_CTX_free() has no return values.

"REMOVED FUNCTIONALITY"
Header "REMOVED FUNCTIONALITY" .Vb 1 void BN_CTX_init(BN_CTX *c); .Ve

\fBBN_CTX_init() is no longer available as of OpenSSL 1.1.0. Applications should replace use of BN_CTX_init with BN_CTX_new instead:

.Vb 6 BN_CTX *ctx; ctx = BN_CTX_new(); if (!ctx) /* error */ ... BN_CTX_free(ctx); .Ve

"SEE ALSO"
Header "SEE ALSO" \fBERR_get_error\|(3), BN_add\|(3), \fBBN_CTX_start\|(3)
"HISTORY"
Header "HISTORY" \fBBN_CTX_init() was removed in OpenSSL 1.1.0.
"COPYRIGHT"
Header "COPYRIGHT" Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at <https://www.openssl.org/source/license.html>.