diff options
Diffstat (limited to 'src/lib/cc')
| -rw-r--r-- | src/lib/cc/.may_include | 1 | ||||
| -rw-r--r-- | src/lib/cc/ctassert.h | 53 | ||||
| -rw-r--r-- | src/lib/cc/include.am | 1 |
3 files changed, 55 insertions, 0 deletions
diff --git a/src/lib/cc/.may_include b/src/lib/cc/.may_include index 2b06e8519c..fa1478ce46 100644 --- a/src/lib/cc/.may_include +++ b/src/lib/cc/.may_include @@ -1 +1,2 @@ orconfig.h +lib/cc/*.h
\ No newline at end of file diff --git a/src/lib/cc/ctassert.h b/src/lib/cc/ctassert.h new file mode 100644 index 0000000000..e42976360f --- /dev/null +++ b/src/lib/cc/ctassert.h @@ -0,0 +1,53 @@ +/* Copyright (c) 2018 The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file ctassert.h + * + * \brief Compile-time assertions: CTASSERT(expression). + */ + +#ifndef TOR_CTASSERT_H +#define TOR_CTASSERT_H + +#include "lib/cc/compat_compiler.h" + +/** + * CTASSERT(expression) + * + * Trigger a compiler error if expression is false. + */ +#if __STDC_VERSION__ >= 201112L + +/* If C11 is available, just use _Static_assert. */ +#define CTASSERT(x) _Static_assert((x), #x) + +#else + +/* + * If C11 is not available, expand __COUNTER__, or __INCLUDE_LEVEL__ + * and __LINE__, or just __LINE__, with an intermediate preprocessor + * macro CTASSERT_EXPN, and then use CTASSERT_DECL to paste the + * expansions together into a unique name. + * + * We use this name as a typedef of an array type with a positive + * length if the assertion is true, and a negative length of the + * assertion is false, which is invalid and hence triggers a compiler + * error. + */ +#if defined(__COUNTER__) +#define CTASSERT(x) CTASSERT_EXPN((x), c, __COUNTER__) +#elif defined(__INCLUDE_LEVEL__) +#define CTASSERT(x) CTASSERT_EXPN((x), __INCLUDE_LEVEL__, __LINE__) +#else +/* hope it's unique enough */ +#define CTASSERT(x) CTASSERT_EXPN((x), l, __LINE__) +#endif + +#define CTASSERT_EXPN(x, a, b) CTASSERT_DECL(x, a, b) +#define CTASSERT_DECL(x, a, b) \ + typedef char tor_ctassert_##a##_##b[(x) ? 1 : -1] ATTR_UNUSED + +#endif + +#endif /* !defined(TOR_CTASSERT_H) */ diff --git a/src/lib/cc/include.am b/src/lib/cc/include.am index 2ae90f97dd..52cf8a9f72 100644 --- a/src/lib/cc/include.am +++ b/src/lib/cc/include.am @@ -1,4 +1,5 @@ noinst_HEADERS += \ src/lib/cc/compat_compiler.h \ + src/lib/cc/ctassert.h \ src/lib/cc/torint.h |