Florian Fischer
9de28df51a
POSIX describes uid_t and gid_t as SIGNED integer types. They need to be able to store -1 for various syscalls.
88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
/// @file stddef.h
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/// @brief Define basic data types.
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/// @copyright (c) 2014-2024 This file is distributed under the MIT License.
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/// See LICENSE.md for details.
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#pragma once
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#ifndef NULL
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/// @brief Define NULL.
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#define NULL ((void *)0)
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#endif
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#ifndef EOF
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/// @brief Define End-Of-File.
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#define EOF (-1)
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#endif
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/// @brief Define the size of a buffer.
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#define BUFSIZ 512
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/// Is the signed integer type of the result of subtracting two pointers.
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typedef long signed int ptrdiff_t;
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/// Define the byte type.
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typedef unsigned char byte_t;
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/// Define the generic size type.
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typedef unsigned long size_t;
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/// Define the generic signed size type.
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typedef long ssize_t;
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/// Define the type of an inode.
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typedef unsigned int ino_t;
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/// Used for device IDs.
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typedef unsigned int dev_t;
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/// The type of user-id.
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typedef int uid_t;
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/// The type of group-id.
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typedef int gid_t;
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/// The type of offset.
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typedef long int off_t;
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/// The type of mode.
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typedef unsigned int mode_t;
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/// This data-type is used to set protection bits of pages.
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typedef unsigned int pgprot_t;
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/// It evaluates to the offset (in bytes) of a given member within
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/// a struct or union type, an expression of type size_t.
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#define offsetof(type, member) \
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((size_t) & (((type *)0)->member))
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/// Retrieve an enclosing structure from a pointer to a nested element.
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#if 1
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#define container_of(ptr, type, member) \
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((type *)((char *)(1 ? (ptr) : &((type *)0)->member) - offsetof(type, member)))
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#else
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#define container_of(ptr, type, member) \
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((type *)((char *)ptr - offsetof(type, member)))
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#endif
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/// Returns the alignment, in bytes, of the specified type.
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#define alignof(type) offsetof( \
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struct { char c; type member; }, member)
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/// Counts the number of elements of an array.
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#define count_of(x) ((sizeof(x) / sizeof((x)[0])) / ((size_t)(!(sizeof(x) % sizeof((x)[0])))))
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/// @brief Swaps two values.
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/// @details
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/// do { ... } while (0) allows to place multistatement operations, for
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/// instance, inside the following if stantement:
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/// if (condition)
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/// swap(var1, var2)
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/// which otherwise would be wrong.
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#define swap(a, b) \
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do { \
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typeof(a) temp = (a); \
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(a) = (b); \
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(b) = temp; \
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} while (0)
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