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Diffstat (limited to '')
l--------- | ccan/ccan/check_type/LICENSE | 1 | ||||
-rw-r--r-- | ccan/ccan/check_type/_info | 33 | ||||
-rw-r--r-- | ccan/ccan/check_type/check_type.h | 64 |
3 files changed, 98 insertions, 0 deletions
diff --git a/ccan/ccan/check_type/LICENSE b/ccan/ccan/check_type/LICENSE new file mode 120000 index 0000000..b7951da --- /dev/null +++ b/ccan/ccan/check_type/LICENSE @@ -0,0 +1 @@ +../../licenses/CC0
\ No newline at end of file diff --git a/ccan/ccan/check_type/_info b/ccan/ccan/check_type/_info new file mode 100644 index 0000000..cc42673 --- /dev/null +++ b/ccan/ccan/check_type/_info @@ -0,0 +1,33 @@ +#include "config.h" +#include <stdio.h> +#include <string.h> + +/** + * check_type - routines for compile time type checking + * + * C has fairly weak typing: ints get automatically converted to longs, signed + * to unsigned, etc. There are some cases where this is best avoided, and + * these macros provide methods for evoking warnings (or build errors) when + * a precise type isn't used. + * + * On compilers which don't support typeof() these routines are less effective, + * since they have to use sizeof() which can only distiguish between types of + * different size. + * + * License: CC0 (Public domain) + * Author: Rusty Russell <rusty@rustcorp.com.au> + */ +int main(int argc, char *argv[]) +{ + if (argc != 2) + return 1; + + if (strcmp(argv[1], "depends") == 0) { +#if !HAVE_TYPEOF + printf("ccan/build_assert\n"); +#endif + return 0; + } + + return 1; +} diff --git a/ccan/ccan/check_type/check_type.h b/ccan/ccan/check_type/check_type.h new file mode 100644 index 0000000..837aef7 --- /dev/null +++ b/ccan/ccan/check_type/check_type.h @@ -0,0 +1,64 @@ +/* CC0 (Public domain) - see LICENSE file for details */ +#ifndef CCAN_CHECK_TYPE_H +#define CCAN_CHECK_TYPE_H +#include "config.h" + +/** + * check_type - issue a warning or build failure if type is not correct. + * @expr: the expression whose type we should check (not evaluated). + * @type: the exact type we expect the expression to be. + * + * This macro is usually used within other macros to try to ensure that a macro + * argument is of the expected type. No type promotion of the expression is + * done: an unsigned int is not the same as an int! + * + * check_type() always evaluates to 0. + * + * If your compiler does not support typeof, then the best we can do is fail + * to compile if the sizes of the types are unequal (a less complete check). + * + * Example: + * // They should always pass a 64-bit value to _set_some_value! + * #define set_some_value(expr) \ + * _set_some_value((check_type((expr), uint64_t), (expr))) + */ + +/** + * check_types_match - issue a warning or build failure if types are not same. + * @expr1: the first expression (not evaluated). + * @expr2: the second expression (not evaluated). + * + * This macro is usually used within other macros to try to ensure that + * arguments are of identical types. No type promotion of the expressions is + * done: an unsigned int is not the same as an int! + * + * check_types_match() always evaluates to 0. + * + * If your compiler does not support typeof, then the best we can do is fail + * to compile if the sizes of the types are unequal (a less complete check). + * + * Example: + * // Do subtraction to get to enclosing type, but make sure that + * // pointer is of correct type for that member. + * #define container_of(mbr_ptr, encl_type, mbr) \ + * (check_types_match((mbr_ptr), &((encl_type *)0)->mbr), \ + * ((encl_type *) \ + * ((char *)(mbr_ptr) - offsetof(encl_type, mbr)))) + */ +#if HAVE_TYPEOF +#define check_type(expr, type) \ + ((typeof(expr) *)0 != (type *)0) + +#define check_types_match(expr1, expr2) \ + ((typeof(expr1) *)0 != (typeof(expr2) *)0) +#else +#include <ccan/build_assert/build_assert.h> +/* Without typeof, we can only test the sizes. */ +#define check_type(expr, type) \ + BUILD_ASSERT_OR_ZERO(sizeof(expr) == sizeof(type)) + +#define check_types_match(expr1, expr2) \ + BUILD_ASSERT_OR_ZERO(sizeof(expr1) == sizeof(expr2)) +#endif /* HAVE_TYPEOF */ + +#endif /* CCAN_CHECK_TYPE_H */ |