✏ 编辑: BUF_MEM_new_ex.3

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.\" ========================================================================
.\"
.IX Title "BUF_MEM_NEW 3"
.TH BUF_MEM_NEW 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
BUF_MEM_new, BUF_MEM_new_ex, BUF_MEM_free, BUF_MEM_grow, BUF_MEM_grow_clean, BUF_reverse \&\- simple character array structure
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/buffer.h>
\&
\& BUF_MEM *BUF_MEM_new(void);
\&
\& BUF_MEM *BUF_MEM_new_ex(unsigned long flags);
\&
\& void BUF_MEM_free(BUF_MEM *a);
\&
\& int BUF_MEM_grow(BUF_MEM *str, int len);
\& size_t BUF_MEM_grow_clean(BUF_MEM *str, size_t len);
\&
\& void BUF_reverse(unsigned char *out, const unsigned char *in, size_t size);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The buffer library handles simple character arrays. Buffers are used for
various purposes in the library, most notably memory BIOs.
.PP
\&\fIBUF_MEM_new()\fR allocates a new buffer of zero size.
.PP
\&\fIBUF_MEM_new_ex()\fR allocates a buffer with the specified flags.
The flag \fB\s-1BUF_MEM_FLAG_SECURE\s0\fR specifies that the \fBdata\fR pointer
should be allocated on the secure heap; see \fICRYPTO_secure_malloc\fR\|(3).
.PP
\&\fIBUF_MEM_free()\fR frees up an already existing buffer. The data is zeroed
before freeing up in case the buffer contains sensitive data.
.PP
\&\fIBUF_MEM_grow()\fR changes the size of an already existing buffer to
\&\fBlen\fR. Any data already in the buffer is preserved if it increases in
size.
.PP
\&\fIBUF_MEM_grow_clean()\fR is similar to \fIBUF_MEM_grow()\fR but it sets any free'd
or additionally-allocated memory to zero.
.PP
\&\fIBUF_reverse()\fR reverses \fBsize\fR bytes at \fBin\fR into \fBout\fR.  If \fBin\fR
is \s-1NULL,\s0 the array is reversed in-place.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fIBUF_MEM_new()\fR returns the buffer or \s-1NULL\s0 on error.
.PP
\&\fIBUF_MEM_free()\fR has no return value.
.PP
\&\fIBUF_MEM_grow()\fR and \fIBUF_MEM_grow_clean()\fR return
zero on error or the new size (i.e., \fBlen\fR).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIbio\fR\|(7),
\&\fICRYPTO_secure_malloc\fR\|(3).
.SH "HISTORY"
.IX Header "HISTORY"
The \fIBUF_MEM_new_ex()\fR function was added in OpenSSL 1.1.0.
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2000\-2018 The OpenSSL Project Authors. All Rights Reserved.
.PP
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>.

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