[#BloombergLP-bslfmt-basic_format_parse_context-check_arg_id]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslfmt.adoc[bslfmt]::xref:BloombergLP/bslfmt/basic_format_parse_context.adoc[basic&lowbar;format&lowbar;parse&lowbar;context]::check&lowbar;arg&lowbar;id
:relfileprefix: ../../../
:mrdocs:

Check that the specified argument index is valid&period;

== Synopsis

Declared in `&lt;bslfmt&lowbar;formatparsecontext&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
void
check&lowbar;arg&lowbar;id(size&lowbar;t id);
----

== Description

If the indexing mode is unset, the indexing mode is set to `e&lowbar;MANUAL`&period; If the indexing mode is `e&lowbar;AUTOMATIC`, caused by a previous call to `next&lowbar;arg&lowbar;id` then an exception of type `format&lowbar;error` is thrown&period; If `id` is not less than the number of arguments then an exception of type `format&lowbar;error` is thrown&period;

== Parameters

[cols="1,4"]
|===
| Name| Description
| *id*
| argument index to validate
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#
