source: branches/minix3-book/include/ansi.h

Last change on this file was 4, checked in by Mattia Monga, 14 years ago

Importazione sorgenti libro

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1/* The <ansi.h> header attempts to decide whether the compiler has enough
2 * conformance to Standard C for Minix to take advantage of. If so, the
3 * symbol _ANSI is defined (as 31459). Otherwise _ANSI is not defined
4 * here, but it may be defined by applications that want to bend the rules.
5 * The magic number in the definition is to inhibit unnecessary bending
6 * of the rules. (For consistency with the new '#ifdef _ANSI" tests in
7 * the headers, _ANSI should really be defined as nothing, but that would
8 * break many library routines that use "#if _ANSI".)
9
10 * If _ANSI ends up being defined, a macro
11 *
12 * _PROTOTYPE(function, params)
13 *
14 * is defined. This macro expands in different ways, generating either
15 * ANSI Standard C prototypes or old-style K&R (Kernighan & Ritchie)
16 * prototypes, as needed. Finally, some programs use _CONST, _VOIDSTAR etc
17 * in such a way that they are portable over both ANSI and K&R compilers.
18 * The appropriate macros are defined here.
19 */
20
21#ifndef _ANSI_H
22#define _ANSI_H
23
24#if __STDC__ == 1
25#define _ANSI 31459 /* compiler claims full ANSI conformance */
26#endif
27
28#ifdef __GNUC__
29#define _ANSI 31459 /* gcc conforms enough even in non-ANSI mode */
30#endif
31
32#ifdef _ANSI
33
34/* Keep everything for ANSI prototypes. */
35#define _PROTOTYPE(function, params) function params
36#define _ARGS(params) params
37
38#define _VOIDSTAR void *
39#define _VOID void
40#define _CONST const
41#define _VOLATILE volatile
42#define _SIZET size_t
43
44#else
45
46/* Throw away the parameters for K&R prototypes. */
47#define _PROTOTYPE(function, params) function()
48#define _ARGS(params) ()
49
50#define _VOIDSTAR void *
51#define _VOID void
52#define _CONST
53#define _VOLATILE
54#define _SIZET int
55
56#endif /* _ANSI */
57
58/* This should be defined as restrict when a C99 compiler is used. */
59#define _RESTRICT
60
61/* Setting any of _MINIX, _POSIX_C_SOURCE or _POSIX2_SOURCE implies
62 * _POSIX_SOURCE. (Seems wrong to put this here in ANSI space.)
63 */
64#if defined(_MINIX) || _POSIX_C_SOURCE > 0 || defined(_POSIX2_SOURCE)
65#undef _POSIX_SOURCE
66#define _POSIX_SOURCE 1
67#endif
68
69#endif /* ANSI_H */
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