BIO_printf, BIO_vprintf, BIO_snprintf, BIO_vsnprintf - formatted output to a BIO

       Copyright 2017-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance
       with the License.  You can obtain a copy in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.

3.5.0                                              2025-06-04                                   BIO_PRINTF(3SSL)

BIO_printf() is similar to the standard C printf() function, except that the output is sent to the
       specified BIO, bio, rather than standard output.  All common format specifiers are supported.

       BIO_vprintf() is similar to the vprintf() function found on many platforms, the output is sent to the
       specified BIO, bio, rather than standard output.  All common format specifiers are supported. The
       argument list args is a stdarg argument list.

       BIO_snprintf() is for platforms that do not have the common snprintf() function. It is like sprintf()
       except that the size parameter, n, specifies the size of the output buffer.

       BIO_vsnprintf() is to BIO_snprintf() as BIO_vprintf() is to BIO_printf().

       BIO_printf, BIO_vprintf, BIO_snprintf, BIO_vsnprintf - formatted output to a BIO

       Except when n is 0, both BIO_snprintf() and BIO_vsnprintf() always terminate their output with '\0'.
       This includes cases where -1 is returned, such as when there is insufficient space to output the whole
       string.

       All functions return the number of bytes written, or -1 on error.  For BIO_snprintf() and BIO_vsnprintf()
       this includes when the output buffer is too small.

        #include <openssl/bio.h>

        int BIO_printf(BIO *bio, const char *format, ...);
        int BIO_vprintf(BIO *bio, const char *format, va_list args);

        int BIO_snprintf(char *buf, size_t n, const char *format, ...);
        int BIO_vsnprintf(char *buf, size_t n, const char *format, va_list args);