Bug 41 – swi-prolog overrides all assertions by defining __assert_fail

Bug 41 - swi-prolog overrides all assertions by defining __assert_fail

Summary:

swi-prolog overrides all assertions by defining __assert_fail

Status:	CONFIRMED

Product:	SWI-Prolog
Classification:	Unclassified
Component:	core
Version:	unspecified
Platform:	PC Linux

Importance:	Highest normal
Assigned To:	Jan Wielemaker

URL:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2012-06-27 17:14 CEST by Ambroz Bizjak
Modified:	2012-06-27 17:14 CEST (History)
CC List:	0 users

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Description Ambroz Bizjak 2012-06-27 17:14:29 CEST

The swipl dynamic library defines the glibc function __assert_fail. This has
the effect that all assertion failures in a program linked to the swipl library
are handled by swipl's assertion failure handler. See:
http://www.swi-prolog.org/git/pl-devel.git/blob/HEAD:/src/pl-thread.c#l5477

This is a problem, because if an assertion failure occurs in a program
embedding SWI-Prolog while the prolog engine is not initialized, the assert
handler will call PL_thread_self(), which will crash.

A possible solution is for SWI-Prolog to use its own assert macro internally
which does whatever it needs to do (and which is only used when the engine is
initialized), and leave the normal assert() behavior unchanged.