Ed Schouten e0cf3b9a3c Make support for thread-unsafe C functions optional.
One of the aspects of CloudABI is that it aims to help you write code
that is thread-safe out of the box. This is very important if you want
to write libraries that are easy to reuse. For CloudABI we decided to
not provide the thread-unsafe functions. So far this is working out
pretty well, as thread-unsafety issues are detected really early on.

The following patch adds a knob to libc++,
_LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS, that can be set to disable
thread-unsafe functions that can easily be avoided in practice. The
following functions are not thread-safe:

- <clocale>: locale handles should be preferred over setlocale().
- <cstdlib>: mbrlen(), mbrtowc() and wcrtomb() should be preferred over
  their non-restartable counterparts.
- <ctime>: asctime(), ctime(), gmtime() and localtime() are not
  thread-safe. The first two are also deprecated by POSIX.

Differential Revision:	http://reviews.llvm.org/D8703
Reviewed by:	marshall

llvm-svn: 240527
2015-06-24 08:44:38 +00:00

56 lines
2.9 KiB
C++

//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// <cstring>
#include <cstring>
#include <type_traits>
#ifndef NULL
#error NULL not defined
#endif
int main()
{
std::size_t s = 0;
void* vp = 0;
const void* vpc = 0;
char* cp = 0;
const char* cpc = 0;
static_assert((std::is_same<decltype(std::memcpy(vp, vpc, s)), void*>::value), "");
static_assert((std::is_same<decltype(std::memmove(vp, vpc, s)), void*>::value), "");
static_assert((std::is_same<decltype(std::strcpy(cp, cpc)), char*>::value), "");
static_assert((std::is_same<decltype(std::strncpy(cp, cpc, s)), char*>::value), "");
static_assert((std::is_same<decltype(std::strcat(cp, cpc)), char*>::value), "");
static_assert((std::is_same<decltype(std::strncat(cp, cpc, s)), char*>::value), "");
static_assert((std::is_same<decltype(std::memcmp(vpc, vpc, s)), int>::value), "");
static_assert((std::is_same<decltype(std::strcmp(cpc, cpc)), int>::value), "");
static_assert((std::is_same<decltype(std::strncmp(cpc, cpc, s)), int>::value), "");
static_assert((std::is_same<decltype(std::strcoll(cpc, cpc)), int>::value), "");
static_assert((std::is_same<decltype(std::strxfrm(cp, cpc, s)), std::size_t>::value), "");
// static_assert((std::is_same<decltype(std::memchr(vpc, 0, s)), const void*>::value), "");
static_assert((std::is_same<decltype(std::memchr(vp, 0, s)), void*>::value), "");
// static_assert((std::is_same<decltype(std::strchr(cpc, 0)), const char*>::value), "");
static_assert((std::is_same<decltype(std::strchr(cp, 0)), char*>::value), "");
static_assert((std::is_same<decltype(std::strcspn(cpc, cpc)), std::size_t>::value), "");
// static_assert((std::is_same<decltype(std::strpbrk(cpc, cpc)), const char*>::value), "");
static_assert((std::is_same<decltype(std::strpbrk(cp, cpc)), char*>::value), "");
// static_assert((std::is_same<decltype(std::strrchr(cpc, 0)), const char*>::value), "");
static_assert((std::is_same<decltype(std::strrchr(cp, 0)), char*>::value), "");
static_assert((std::is_same<decltype(std::strspn(cpc, cpc)), std::size_t>::value), "");
// static_assert((std::is_same<decltype(std::strstr(cpc, cpc)), const char*>::value), "");
static_assert((std::is_same<decltype(std::strstr(cp, cpc)), char*>::value), "");
#ifndef _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
static_assert((std::is_same<decltype(std::strtok(cp, cpc)), char*>::value), "");
#endif
static_assert((std::is_same<decltype(std::memset(vp, 0, s)), void*>::value), "");
static_assert((std::is_same<decltype(std::strerror(0)), char*>::value), "");
static_assert((std::is_same<decltype(std::strlen(cpc)), std::size_t>::value), "");
}