[#BIO_nread0]
= BIO_nread0
:mrdocs:

Peek at readable bytes in a memory BIO without consuming them.

== Synopsis

Declared in `<openssl/bio.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
int
BIO_nread0(
    xref:BIO.adoc[BIO]* bio,
    char** buf);
----

== Return Value

Number of bytes available at *`buf,` or a negative value on error.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *bio*
| Memory BIO to inspect.
| *buf*
| Receives a pointer into the BIO's internal buffer (valid until the next modify).
|===


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