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/Haskell 9

GHC.Stack.CloneStack

Safe Haskell None
Language Haskell2010

Description

This module exposes an interface for capturing the state of a thread's execution stack for diagnostics purposes: cloneMyStack, cloneThreadStack.

Such a "cloned" stack can be decoded with decode to a stack trace, given that the -finfo-table-map is enabled.

Since: base-4.17.0.0

data StackSnapshot Source

A frozen snapshot of the state of an execution stack.

Since: base-4.17.0.0

Constructors

StackSnapshot !StackSnapshot#

data StackEntry Source

Representation for the source location where a return frame was pushed on the stack. This happens every time when a case ... of scrutinee is evaluated.

Constructors

StackEntry

Fields

Instances
Instances details
Show StackEntry Source
Instance details

Defined in GHC.Internal.Stack.CloneStack

Methods

showsPrec :: Int -> StackEntry -> ShowS Source

show :: StackEntry -> String Source

showList :: [StackEntry] -> ShowS Source

Eq StackEntry Source
Instance details

Defined in GHC.Internal.Stack.CloneStack

Methods

(==) :: StackEntry -> StackEntry -> Bool Source

(/=) :: StackEntry -> StackEntry -> Bool Source

cloneMyStack :: IO StackSnapshot Source

Clone the stack of the executing thread

Since: base-4.17.0.0

cloneThreadStack :: ThreadId -> IO StackSnapshot Source

Clone the stack of a thread identified by its ThreadId

Since: base-4.17.0.0

decode :: StackSnapshot -> IO [StackEntry] Source

Decode a StackSnapshot to a stacktrace (a list of StackEntry). The stack trace is created from return frames with according InfoProvEnt entries. To generate them, use the GHC flag -finfo-table-map. If there are no InfoProvEnt entries, an empty list is returned.

Please note:

  • To gather StackEntry from libraries, these have to be compiled with -finfo-table-map, too.
  • Due to optimizations by GHC (e.g. inlining) the stacktrace may change with different GHC parameters and versions.
  • The stack trace is empty (by design) if there are no return frames on the stack. (These are pushed every time when a case ... of scrutinee is evaluated.)

Since: base-4.17.0.0

© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/9.12.1/docs/libraries/base-4.21.0.0-8e62/GHC-Stack-CloneStack.html