[exec.get.fwd.progress]

# 33 Execution control library [[exec]](./#exec)

## 33.5 Queries [[exec.queries]](exec.queries#exec.get.fwd.progress)

### 33.5.8 execution​::​get_forward_progress_guarantee [exec.get.fwd.progress]

namespace std::execution {enum class [forward_progress_guarantee](#lib:forward_progress_guarantee "33.5.8 execution​::​get_­forward_­progress_­guarantee [exec.get.fwd.progress]") { concurrent,
 parallel,
 weakly_parallel };}

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L1001)

get_forward_progress_guarantee asks a scheduler about
the forward progress guarantee of execution agents
created by that scheduler's associated execution resource ([[intro.progress]](intro.progress "6.10.2.3 Forward progress"))[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L1006)

The name get_forward_progress_guarantee denotes a query object[.](#2.sentence-1)

For a subexpression sch, let Sch be decltype((sch))[.](#2.sentence-2)

If Sch does not satisfy [scheduler](exec.sched#concept:scheduler "33.6 Schedulers [exec.sched]"),get_forward_progress_guarantee is ill-formed[.](#2.sentence-3)

Otherwise,get_forward_progress_guarantee(sch) is expression-equivalent to:

- [(2.1)](#2.1)

  *MANDATE-NOTHROW*(*AS-CONST*(sch).query(get_forward_progress_guarantee)),
if that expression is well-formed[.](#2.1.sentence-1)
  *Mandates*: The type of the expression above is forward_progress_guarantee[.](#2.1.sentence-2)

- [(2.2)](#2.2)

  Otherwise, forward_progress_guarantee​::​weakly_parallel[.](#2.2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/exec.tex#L1024)

If get_forward_progress_guarantee(sch) for some scheduler sch returns forward_progress_guarantee​::​concurrent,
all execution agents created by that scheduler's associated execution resource
shall provide the concurrent forward progress guarantee[.](#3.sentence-1)

If it returns forward_progress_guarantee​::​parallel,
all such execution agents
shall provide at least the parallel forward progress guarantee[.](#3.sentence-2)