Cleanup: namespace 'align' macros
[lttng-tools.git] / src / common / macros.h
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990570ed 1/*
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2 * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
3 * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
990570ed 4 *
ab5be9fa 5 * SPDX-License-Identifier: GPL-2.0-only
990570ed 6 *
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7 */
8
9#ifndef _MACROS_H
10#define _MACROS_H
11
12#include <stdlib.h>
93375aa6 13#include <stddef.h>
f6835b82 14#include <string.h>
639082d2 15#include <common/compat/string.h>
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16
17/*
18 * Takes a pointer x and transform it so we can use it to access members
19 * without a function call. Here an example:
20 *
21 * #define GET_SIZE(x) LTTNG_REF(x)->size
22 *
23 * struct { int size; } s;
24 *
25 * printf("size : %d\n", GET_SIZE(&s));
26 *
27 * For this example we can't use something like this for compatibility purpose
28 * since this will fail:
29 *
30 * #define GET_SIZE(x) x->size;
31 *
32 * This is mostly use for the compatibility layer of lttng-tools. See
33 * poll/epoll for a good example. Since x can be on the stack or allocated
34 * memory using malloc(), we must use generic accessors for compat in order to
35 * *not* use a function to access members and not the variable name.
36 */
37#define LTTNG_REF(x) ((typeof(*x) *)(x))
38
39/*
40 * Memory allocation zeroed
41 */
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42static inline
43void *zmalloc(size_t len)
44{
45 return calloc(1, len);
46}
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47
48#ifndef ARRAY_SIZE
49#define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0])))
50#endif
51
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52#ifndef container_of
53#define container_of(ptr, type, member) \
54 ({ \
55 const typeof(((type *)NULL)->member) * __ptr = (ptr); \
56 (type *)((char *)__ptr - offsetof(type, member)); \
57 })
58#endif
59
cf3f19ae 60
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61/*
62 * The min and max macros are not needed in C++ (std::min and std::max are
63 * preferred) and they conflict with some C++ header file. Don't define them
64 * when compiling C++ source.
65 */
66#ifndef __cplusplus
331744e3 67
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68# ifndef max
69# define max(a, b) ((a) > (b) ? (a) : (b))
70# endif
71
72# ifndef min
73# define min(a, b) ((a) < (b) ? (a) : (b))
74# endif
75
76# ifndef max_t
77# define max_t(type, a, b) max((type) a, (type) b)
78# endif
79
80# ifndef min_t
81# define min_t(type, a, b) min((type) a, (type) b)
82# endif
cf3f19ae 83
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84#endif
85
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86#ifndef LTTNG_PACKED
87#define LTTNG_PACKED __attribute__((__packed__))
88#endif
89
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90#ifndef LTTNG_NO_SANITIZE_ADDRESS
91#if defined(__clang__) || defined (__GNUC__)
92#define LTTNG_NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
93#else
94#define LTTNG_NO_SANITIZE_ADDRESS
95#endif
96#endif
97
0c634962 98#define is_signed(type) (((type) -1) < (type) 1)
159b042f 99
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100#define member_sizeof(type, field) sizeof(((type *) 0)->field)
101
a0377dfe 102#define ASSERT_LOCKED(lock) LTTNG_ASSERT(pthread_mutex_trylock(&lock))
5e5c14ce 103
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104/*
105 * Get an aligned pointer to a value. This is meant
106 * as a helper to pass an aligned pointer to a member in a packed structure
107 * to a function.
108 */
109#define ALIGNED_CONST_PTR(value) (((const typeof(value) []) { value }))
110
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111/*
112 * lttng_strncpy returns 0 on success, or nonzero on failure.
113 * It checks that the @src string fits into @dst_len before performing
114 * the copy. On failure, no copy has been performed.
115 *
116 * dst_len includes the string's trailing NULL.
117 */
118static inline
119int lttng_strncpy(char *dst, const char *src, size_t dst_len)
120{
c3ef76cd 121 if (lttng_strnlen(src, dst_len) >= dst_len) {
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122 /* Fail since copying would result in truncation. */
123 return -1;
124 }
c3ef76cd 125 strcpy(dst, src);
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126 return 0;
127}
128
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129#ifdef NDEBUG
130/*
131* Force usage of the assertion condition to prevent unused variable warnings
132* when `assert()` are disabled by the `NDEBUG` definition.
133*/
134# define LTTNG_ASSERT(_cond) ((void) sizeof((void) (_cond), 0))
135#else
136# include <assert.h>
137# define LTTNG_ASSERT(_cond) assert(_cond)
138#endif
139
990570ed 140#endif /* _MACROS_H */
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