projects / babeltrace.git / blame
| Commit | Line | Data |
|---|---|---|
| eb31c5e6 | 1 | /* |
| 0235b0db | 2 | * SPDX-License-Identifier: MIT |
| eb31c5e6 | 3 | * |
| 0235b0db | 4 | * Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| eb31c5e6 | 5 | */ |
| fd3c708f | 6 | |
| 0235b0db MJ |
7 | #ifndef _BABELTRACE_INTERNAL_H |
| 8 | #define _BABELTRACE_INTERNAL_H | |
| 70bd0a12 | 9 | |
| 91d81473 | 10 | #define bt_max_t(type, a, b) \ |
| f3e4505b | 11 | ((type) (a) > (type) (b) ? (type) (a) : (type) (b)) |
| f3e4505b | 12 | |
| 5d6c80a5 JD |
13 | /* |
| 14 | * BT_HIDDEN: set the hidden attribute for internal functions | |
| 675860f4 MJ |
15 | * On Windows, symbols are local unless explicitly exported, |
| 16 | * see https://gcc.gnu.org/wiki/Visibility | |
| 5d6c80a5 | 17 | */ |
| 675860f4 MJ |
18 | #if defined(_WIN32) || defined(__CYGWIN__) |
| 19 | #define BT_HIDDEN | |
| 20 | #else | |
| 5d6c80a5 | 21 | #define BT_HIDDEN __attribute__((visibility("hidden"))) |
| 675860f4 | 22 | #endif |
| 5d6c80a5 | 23 | |
| 55b71f05 SM |
24 | /* |
| 25 | * Yield `ref`'s value while setting `ref` to NULL. | |
| 26 | * | |
| 27 | * This can be used to give a strong reference to a callee: | |
| 28 | * | |
| 29 | * add_foo_to_list(list, BT_MOVE_REF(foo)); | |
| 30 | * | |
| 31 | * or in a simple assignment: | |
| 32 | * | |
| 33 | * my_struct->foo = BT_MOVE_REF(foo); | |
| 34 | * | |
| 35 | * When moving a reference in a function call, the reference is given to the | |
| 36 | * callee even if that function call fails, so make sure the called function | |
| 37 | * is written accordingly. | |
| 38 | */ | |
| 39 | ||
| 40 | #define BT_MOVE_REF(ref) \ | |
| 41 | ({ \ | |
| e3d110d6 | 42 | typeof(ref) _ref = ref; \ |
| 55b71f05 SM |
43 | ref = NULL; \ |
| 44 | _ref; \ | |
| 45 | }) | |
| 46 | ||
| 1778c2a4 PP |
47 | /* |
| 48 | * Copied from: | |
| 49 | * <https://stackoverflow.com/questions/37411809/how-to-elegantly-fix-this-unused-variable-warning/37412551#37412551>: | |
| 50 | * | |
| 51 | * * sizeof() ensures that the expression is not evaluated at all, so | |
| 52 | * its side-effects don't happen. That is to be consistent with the | |
| 53 | * usual behaviour of debug-only constructs, such as assert(). | |
| 54 | * | |
| 55 | * * `((_expr), 0)` uses the comma operator to swallow the actual type | |
| 56 | * of `(_expr)`. This is to prevent VLAs from triggering evaluation. | |
| 57 | * | |
| 58 | * * `(void)` explicitly ignores the result of `(_expr)` and sizeof() so | |
| 59 | * no "unused value" warning appears. | |
| 60 | */ | |
| 61 | ||
| 62 | #define BT_USE_EXPR(_expr) ((void) sizeof((void) (_expr), 0)) | |
| 63 | #define BT_USE_EXPR2(_expr1, _expr2) \ | |
| 64 | ((void) sizeof((void) (_expr1), (void) (_expr2), 0)) | |
| 65 | #define BT_USE_EXPR3(_expr1, _expr2, _expr3) \ | |
| 66 | ((void) sizeof((void) (_expr1), (void) (_expr2), (void) (_expr3), 0)) | |
| 67 | #define BT_USE_EXPR4(_expr1, _expr2, _expr3, _expr4) \ | |
| 68 | ((void) sizeof((void) (_expr1), (void) (_expr2), \ | |
| 69 | (void) (_expr3), (void) (_expr4), 0)) | |
| 70 | #define BT_USE_EXPR5(_expr1, _expr2, _expr3, _expr4, _expr5) \ | |
| 71 | ((void) sizeof((void) (_expr1), (void) (_expr2), \ | |
| 72 | (void) (_expr3), (void) (_expr4), (void) (_expr5), 0)) | |
| 73 | ||
| 70bd0a12 | 74 | #endif |