SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
brief: |
  Establishes an interrupt service routine.
copyrights:
- Copyright (C) 2021 embedded brains GmbH (http://www.embedded-brains.de)
- Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
definition:
  default:
    attributes: null
    body: null
    params:
    - ${isr-entry:/name} ${.:/params[0]/name}
    - ${vector-number:/name} ${.:/params[1]/name}
    - ${isr-entry:/name} *${.:/params[2]/name}
    return: ${../../status/if/code:/name}
  variants: []
description: |
  This directive establishes an interrupt service routine (ISR) for the
  interrupt specified by the ${.:/params[1]/name} number.  The
  ${.:/params[0]/name} parameter specifies the entry point of the ISR.  The
  entry point of the previous ISR for the specified vector is returned in
  ${.:/params[2]/name}.

  To release an interrupt vector, pass the old handler's address obtained when
  the vector was first capture.
enabled-by: true
index-entries:
- establish an ISR
- install an ISR
interface-type: function
links:
- role: interface-placement
  uid: header
- role: interface-ingroup
  uid: group
- role: constraint
  uid: /constraint/directive-not-pre-qualified
- role: constraint
  uid: /constraint/directive-ctx-isr
- role: constraint
  uid: /constraint/directive-ctx-devinit
- role: constraint
  uid: /constraint/directive-ctx-task
- role: constraint
  uid: /constraint/directive-no-preempt
- role: constraint
  uid: /constraint/cpu-simple-vectored-interrupts
name: rtems_interrupt_catch
notes: null
params:
- description: |
    is the new interrupt service routine.
  dir: null
  name: new_isr_handler
- description: |
    is the interrupt vector number.
  dir: null
  name: vector
- description: |
    is the pointer to an ${isr-entry:/name} object.  When the directive call is
    successful, the previous interrupt service routine established for this
    interrupt vector will be stored in this object.
  dir: out
  name: old_isr_handler
return:
  return: null
  return-values:
  - description: |
      The requested operation was successful.
    value: ${../../status/if/successful:/name}
  - description: |
      The interrupt vector number was illegal.
    value: ${../../status/if/invalid-number:/name}
  - description: |
      The ${.:/params[0]/name} parameter was ${/c/if/null:/name}.
    value: ${../../status/if/invalid-address:/name}
  - description: |
      The ${.:/params[2]/name} parameter was ${/c/if/null:/name}.
    value: ${../../status/if/invalid-address:/name}
type: interface