[#BloombergLP-bslmf-InvokeResultDeductionFailed]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslmf.adoc[bslmf]::InvokeResultDeductionFailed
:relfileprefix: ../../
:mrdocs:

When `invoke_result` cannot deduce the actual return type of a functor (in C++03 mode), it yields this type as a placeholder. The advantage of using this placeholder instead of a compilation failure (e.g., using a static assert) is that the return type of an INVOKE() operation is often discarded, so our failure to deduce the return type is often harmless. Since `InvokeResultDeductionFailed` is a return type, it must be convertible from the actual return type; this conversion is accomplished by means of a constructor that makes it convertible from _any_ type.

== Synopsis

Declared in `<bslmf_invokeresult.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
struct InvokeResultDeductionFailed;
----

== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslmf/InvokeResultDeductionFailed/2constructor.adoc[`InvokeResultDeductionFailed`]         [.small]#[constructor]#
| Convert from an arbitrary type. The actual argument value is discarded.
|===



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