BIO_PRINTF(3) | Library Functions Manual | BIO_PRINTF(3)

# NAME

`BIO_printf` — formatted output to a BIO

# SYNOPSIS

library “libcrypto”
`#include <openssl/bio.h>`

int
`BIO_printf`(BIO *bio, const char *format, ...);

# DESCRIPTION

`BIO_printf`() is a wrapper around vfprintf(3), sending the output to the specified bio.

# RETURN VALUES

These functions return the number of bytes written, or -1 if an error occurs.

# SEE ALSO

BIO_new(3)

# HISTORY

`BIO_printf`() first appeared in SSLeay 0.6.5 and has been available since OpenBSD 2.4.

June 8, 2025 | Debian