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.\"
.\" This file and its contents are supplied under the terms of the
.\" Common Development and Distribution License ("CDDL"), version 1.0.
.\" You may only use this file in accordance with the terms of version
.\" 1.0 of the CDDL.
.\"
.\" A full copy of the text of the CDDL should have accompanied this
.\" source. A copy of the CDDL is also available via the Internet at
.\" http://www.illumos.org/license/CDDL.
.\"
.\"
.\" Copyright 2018 Nexenta Systems, Inc.
.\"
.Dd August 12, 2017
.Dt SET_CONSTRAINT_HANDLER_S 3C
.Os
.Sh NAME
.Nm set_constraint_handler_s ,
.Nm abort_handler_s ,
.Nm ignore_handler_s
.Nd runtime-constraint handling
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #define __STDC_WANT_LIB_EXT1__ 1
.In stdlib.h
.Ft constraint_handler_t
.Fo set_constraint_handler_s
.Fa "constraint_handler_t handler"
.Fc
.Ft void
.Fo abort_handler_s
.Fa "const char *restrict msg"
.Fa "void *restrict ptr"
.Fa "errno_t error"
.Fc
.Ft void
.Fo ignore_handler_s
.Fa "const char *restrict msg"
.Fa "void *restrict ptr"
.Fa "errno_t error"
.Fc
.Sh DESCRIPTION
The
.Fn set_constraint_handler_s
function sets the runtime-constraint handler to be
.Fa handler .
.Pp
The runtime-constraint handler is the callback function invoked when a library
function detects a runtime-constraint violation, having the following prototype:
.Bd -literal -offset indent
void (*constraint_handler_t)(const char *restrict msg,
void *restrict ptr, errno_t error);
.Ed
.Pp
The arguments are as follows:
.Bl -tag -width "error"
.It Fa msg
A pointer to a character string describing the runtime-constraint violation.
.It Fa ptr
A
.Dv NULL
pointer.
.It Fa error
If the function calling the handler has a return type declared as
.Vt errno_t ,
the return value of the function is passed.
Otherwise, a positive value of type
.Vt errno_t
is passed.
.El
.Pp
Only the most recent handler registered with
.Fn set_constraint_handler_s
is called when a runtime-constraint violation occurs.
.Pp
The implementation has a default constraint handler that is used if no calls to
the
.Fn set_constraint_handler_s
function have been made.
If the
.Fa handler
argument to
.Fn set_constraint_handler_s
is a
.Dv NULL
pointer, the default handler becomes the current constraint handler.
.Pp
The
.Fn abort_handler_s
and
.Fn ignore_handler_s
are the standard-defined runtime-constraint handlers provided by the C library.
.Pp
The
.Fn abort_handler_s
function writes the error message including the
.Fa msg
to
.Dv stderr
and calls the
.Xr abort 3C
function.
The
.Fn abort_handler_s
is currently the default runtime-constraint handler.
.Pp
The
.Fn ignore_handler_s
simply returns to its caller.
.Sh RETURN VALUES
The
.Fn set_constraint_handler_s
function returns a pointer to the previously registered handler, or
.Dv NULL
if none was previously registered.
.Pp
The
.Fn abort_handler_s
function does not return to its caller.
.Pp
The
.Fn ignore_handler_s
function returns no value.
.Sh INTERFACE STABILITY
.Sy Standard
.Sh MT-LEVEL
.Sy Safe
.Sh STANDARDS
The
.Fn set_constraint_handler_s
function conforms to
.St -isoC-2011 .
|
