libc/winsup/cygwin/lib/atexit.c

35 lines
1.2 KiB
C

/* atexit.c: atexit entry point
Copyright 2014 Red Hat, Inc.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include <stddef.h>
#include <windows.h>
/* Statically linked replacement for the former cygwin_atexit. We need
the function here to be able to access the correct __dso_handle of the
caller's DSO. */
int
atexit (void (*fn) (void))
{
extern int __cxa_atexit(void (*)(void*), void*, void*);
extern void *__dso_handle;
extern void *__ImageBase;
/* Check for being called from inside the executable. If so, use NULL
as __dso_handle. This allows to link executables with GCC versions
not providing __dso_handle in crtbegin{S}.o. In this case our own
__dso_handle defined in lib/dso_handle.c is used. However, our
__dso_handle always points to &__ImageBase, while the __dso_handle
for executables provided by crtbegin.o usually points to NULL.
That's what we remodel here. */
return __cxa_atexit ((void (*)(void*))fn, NULL,
&__ImageBase == (void **) GetModuleHandleW (NULL)
? NULL : &__dso_handle);
}