From c8a9c22173f485c8c053709e1dfa0a617cb6be1a Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sun, 24 Nov 2013 21:42:55 -0500 Subject: restore type of NULL to void * except when used in C++ programs unfortunately this eliminates the ability of the compiler to diagnose some dangerous/incorrect usage, but POSIX requires (as an extension to the C language, i.e. CX shaded) that NULL have type void *. plain C allows it to be defined as any null pointer constant. the definition 0L is preserved for C++ rather than reverting to plain 0 to avoid dangerous behavior in non-conforming programs which use NULL as a variadic sentinel. (it's impossible to use (void *)0 for C++ since C++ lacks the proper implicit pointer conversions, and other popular alternatives like the GCC __null extension seem non-conforming to the standard's requirements.) --- include/locale.h | 4 ++++ include/stddef.h | 4 ++++ include/stdio.h | 4 ++++ include/stdlib.h | 4 ++++ include/string.h | 4 ++++ include/time.h | 5 +++++ include/unistd.h | 4 ++++ include/wchar.h | 4 ++++ 8 files changed, 33 insertions(+) (limited to 'include') diff --git a/include/locale.h b/include/locale.h index 7e80fd93..ce384381 100644 --- a/include/locale.h +++ b/include/locale.h @@ -7,7 +7,11 @@ extern "C" { #include +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #define LC_CTYPE 0 #define LC_NUMERIC 1 diff --git a/include/stddef.h b/include/stddef.h index 9d522486..0a329190 100644 --- a/include/stddef.h +++ b/include/stddef.h @@ -1,7 +1,11 @@ #ifndef _STDDEF_H #define _STDDEF_H +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #define __NEED_ptrdiff_t #define __NEED_size_t diff --git a/include/stdio.h b/include/stdio.h index cd60bb55..884d2e6a 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -21,7 +21,11 @@ extern "C" { #include +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #undef EOF #define EOF (-1) diff --git a/include/stdlib.h b/include/stdlib.h index 2bd5f102..1e67b896 100644 --- a/include/stdlib.h +++ b/include/stdlib.h @@ -7,7 +7,11 @@ extern "C" { #include +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #define __NEED_size_t #define __NEED_wchar_t diff --git a/include/string.h b/include/string.h index d4412333..ff9badb9 100644 --- a/include/string.h +++ b/include/string.h @@ -7,7 +7,11 @@ extern "C" { #include +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #define __NEED_size_t #if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \ diff --git a/include/time.h b/include/time.h index 6e499ffe..70574093 100644 --- a/include/time.h +++ b/include/time.h @@ -7,7 +7,12 @@ extern "C" { #include +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif + #define __NEED_size_t #define __NEED_time_t diff --git a/include/unistd.h b/include/unistd.h index a00a9c4f..9f2fac96 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -15,7 +15,11 @@ extern "C" { #define SEEK_CUR 1 #define SEEK_END 2 +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #define __NEED_size_t #define __NEED_ssize_t diff --git a/include/wchar.h b/include/wchar.h index fd5aac5f..9fd967cc 100644 --- a/include/wchar.h +++ b/include/wchar.h @@ -33,7 +33,11 @@ extern "C" { #define WCHAR_MIN (-1-0x7fffffff+L'\0') #endif +#ifdef __cplusplus #define NULL 0L +#else +#define NULL ((void*)0) +#endif #undef WEOF #define WEOF 0xffffffffU -- cgit v1.2.1