Commit f619c460 authored by Nick Mathewson's avatar Nick Mathewson 🎨
Browse files

Add an autoconf test to make sure that memset(&ptr, 0, sizeof(ptr)) and ptr=NULL are equivalent


svn:r2536
parent 56a592db
......@@ -195,6 +195,21 @@ if test $tor_cv_unaligned_ok = yes; then
[Define to 1 iff unaligned int access is allowed])
fi
# Now make sure that NULL can be represented as zero bytes.
AC_CACHE_CHECK([whether memset(0) sets pointers to NULL], tor_cv_null_is_zero,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[[#include <stdlib.h>
int main () { char *p1,*p2; p1=NULL; memset(&p2,0,sizeof(p2));
return memcmp(&p1,&p2,sizeof(char*)); }]])],
[tor_cv_null_is_zero=yes],
[tor_cv_null_is_zero=no],
[tor_cv_null_is_zero=cross])])
if test $tor_cv_null_is_zero = yes; then
AC_DEFINE([NULL_REP_IS_ZERO_BYTES], 1,
[Define to 1 iff memset(0) sets pointers to NULL])
fi
# $prefix stores the value of the --prefix command line option, or
# NONE if the option wasn't set. In the case that it wasn't set, make
# it be the default, so that we can use it to expand directories now.
......
......@@ -20,6 +20,10 @@
#include <time.h>
#endif
#ifndef NULL_REP_IS_ZERO_BYTES
#error "It seems your platform does not represent NULL as zero. We can't cope."
#endif
#if _MSC_VER > 1300
#include <winsock2.h>
#include <ws2tcpip.h>
......
......@@ -124,11 +124,13 @@
/* Define to 1 if you have the <unistd.h> header file. */
#undef HAVE_UNISTD_H
/* Define to 1 iff unaligned int access is allowed */
#define NULL_REP_IS_ZERO_BYTES 1
/* Name of package */
#define PACKAGE "tor"
/* Def
ine to the address where bug reports for this package should be sent. */
/* Define to the address where bug reports for this package should be sent. */
#undef PACKAGE_BUGREPORT
/* Define to the full name of this package. */
......
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