[#bsl-basic_syncbuf-showmanyc-05]
= xref:bsl.adoc[bsl]::xref:bsl/basic_syncbuf.adoc[basic&lowbar;syncbuf]::showmanyc
:relfileprefix: ../../
:mrdocs:

Investigating the data available&period;

== Synopsis

Declared in `&lt;bslstl&lowbar;syncbuf&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
virtual
streamsize
showmanyc();
----

== Description

_If it returns a positive value, then successive calls to_ `underflow()` will not return `traits&colon;&colon;eof()` until at least that number of characters have been supplied&period; If `showmanyc()` returns &hyphen;1, then calls to `underflow()` or `uflow()` will fail&period; &lsqb;27&period;5&period;2&period;4&period;3&rsqb;&sol;1

[NOTE]
====
Base class version does nothing, returns zero&period;

====

[NOTE]
====
The standard adds that _the intention is not only that the_ calls &lsqb;to underflow or uflow&rsqb;will not return `eof()` but that they will return immediately&period;

====

[NOTE]
====
The standard adds that _the morphemes of _`showmanyc` are *es&hyphen;how&hyphen;many&hyphen;see,* not *show&hyphen;manic&period;*

====

== Return Value

An estimate of the number of characters available in the input sequence, or &hyphen;1&period;


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