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[perl5.git] / perlvars.h
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1/* perlvars.h
2 *
663f364b 3 * Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
54ca4ee7 4 * by Larry Wall and others
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5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Artistic License, as specified in the README file.
8 *
9 */
10
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11/*
12=head1 Global Variables
e8570548 13These variables are global to an entire process. They are shared between
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14all interpreters and all threads in a process. Any variables not documented
15here may be changed or removed without notice, so don't use them!
16If you feel you really do need to use an unlisted variable, first send email to
17L<perl5-porters@perl.org|mailto:perl5-porters@perl.org>. It may be that
18someone there will point out a way to accomplish what you need without using an
19internal variable. But if not, you should get a go-ahead to document and then
20use the variable.
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21
22=cut
88e1f1a2 23*/
49f531da 24
d7cb65f2 25/* Don't forget to re-run regen/embed.pl to propagate changes! */
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26
27/* This file describes the "global" variables used by perl
28 * This used to be in perl.h directly but we want to abstract out into
29 * distinct files which are per-thread, per-interpreter or really global,
30 * and how they're initialized.
31 *
32 * The 'G' prefix is only needed for vars that need appropriate #defines
22c35a8c 33 * generated in embed*.h. Such symbols are also used to generate
14dd3ad8 34 * the appropriate export list for win32. */
cb68f92d 35
49f531da 36/* global state */
eeb6b841 37#if defined(USE_ITHREADS)
115ff745 38PERLVAR(G, op_mutex, perl_mutex) /* Mutex for op refcounting */
eeb6b841 39#endif
5c64bffd 40PERLVARI(G, curinterp, PerlInterpreter *, NULL)
43165c05 41 /* currently running interpreter
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42 * (initial parent interpreter under
43 * useithreads) */
3db8f154 44#if defined(USE_ITHREADS)
115ff745 45PERLVAR(G, thr_key, perl_key) /* key to retrieve per-thread struct */
ba869deb 46#endif
a0ed51b3 47
43165c05 48/* XXX does anyone even use this? */
115ff745 49PERLVARI(G, do_undump, bool, FALSE) /* -u or dump seen? */
b363f7ed 50
eeb6b841 51#ifndef PERL_USE_SAFE_PUTENV
115ff745 52PERLVARI(G, use_safe_putenv, bool, TRUE)
b363f7ed 53#endif
534825c4 54
eeb6b841 55#if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS)||defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
115ff745 56PERLVARI(G, sig_handlers_initted, int, 0)
534825c4 57#endif
eeb6b841 58#ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
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59PERLVARA(G, sig_ignoring, SIG_SIZE, int)
60 /* which signals we are ignoring */
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61#endif
62#ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
115ff745 63PERLVARA(G, sig_defaulting, SIG_SIZE, int)
d90a703e 64#endif
5c728af0 65
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66/* XXX signals are process-wide anyway, so we
67 * ignore the implications of this for threading */
68#ifndef HAS_SIGACTION
115ff745 69PERLVARI(G, sig_trapped, int, 0)
428eed4a 70#endif
af419de7 71
2f42fcb0 72#ifndef PERL_MICRO
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73/* If Perl has to ignore SIGPFE, this is its saved state.
74 * See perl.h macros PERL_FPU_INIT and PERL_FPU_{PRE,POST}_EXEC. */
115ff745 75PERLVAR(G, sigfpe_saved, Sighandler_t)
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76
77/* these ptrs to functions are to avoid linkage problems; see
78 * perl-5.8.0-2193-g5c1546dc48
79 */
80PERLVARI(G, csighandlerp, Sighandler_t, Perl_csighandler)
81PERLVARI(G, csighandler1p, Sighandler1_t, Perl_csighandler1)
82PERLVARI(G, csighandler3p, Sighandler3_t, Perl_csighandler3)
2f42fcb0 83#endif
5c1546dc 84
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85/* This is constant on most architectures, a global on OS/2 */
86#ifdef OS2
115ff745 87PERLVARI(G, sh_path, char *, SH_PATH) /* full path of shell */
50acdf95 88#endif
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89
90#ifdef USE_PERLIO
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91
92# if defined(USE_ITHREADS)
115ff745 93PERLVAR(G, perlio_mutex, perl_mutex) /* Mutex for perlio fd refcounts */
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94# endif
95
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96PERLVARI(G, perlio_fd_refcnt, int *, 0) /* Pointer to array of fd refcounts. */
97PERLVARI(G, perlio_fd_refcnt_size, int, 0) /* Size of the array */
98PERLVARI(G, perlio_debug_fd, int, 0) /* the fd to write perlio debug into, 0 means not set yet */
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99#endif
100
101#ifdef HAS_MMAP
115ff745 102PERLVARI(G, mmap_page_size, IV, 0)
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103#endif
104
eeb6b841 105#if defined(USE_ITHREADS)
115ff745 106PERLVAR(G, hints_mutex, perl_mutex) /* Mutex for refcounted he refcounting */
2bc5f86a 107PERLVAR(G, env_mutex, perl_mutex) /* Mutex for accessing ENV */
69c5e0db 108# if ! defined(USE_THREAD_SAFE_LOCALE) || defined(TS_W32_BROKEN_LOCALECONV)
929e1213 109PERLVAR(G, locale_mutex, perl_mutex) /* Mutex for setlocale() changing */
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110# endif
111# ifndef USE_THREAD_SAFE_LOCALE
49d7d366 112PERLVAR(G, lc_numeric_mutex, perl_mutex) /* Mutex for switching LC_NUMERIC */
423a80b7 113# endif
5acc3fa5 114#endif
6ebbc862 115
39e69e77 116#ifdef USE_POSIX_2008_LOCALE
5acc3fa5 117PERLVAR(G, C_locale_obj, locale_t)
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118#endif
119
0c5ea019 120PERLVARI(G, watch_pvx, char *, NULL)
27da23d5 121
e8570548 122/*
78342678 123=for apidoc AmnU|Perl_check_t *|PL_check
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124
125Array, indexed by opcode, of functions that will be called for the "check"
126phase of optree building during compilation of Perl code. For most (but
127not all) types of op, once the op has been initially built and populated
128with child ops it will be filtered through the check function referenced
129by the appropriate element of this array. The new op is passed in as the
130sole argument to the check function, and the check function returns the
131completed op. The check function may (as the name suggests) check the op
132for validity and signal errors. It may also initialise or modify parts of
133the ops, or perform more radical surgery such as adding or removing child
134ops, or even throw the op away and return a different op in its place.
135
136This array of function pointers is a convenient place to hook into the
137compilation process. An XS module can put its own custom check function
138in place of any of the standard ones, to influence the compilation of a
139particular type of op. However, a custom check function must never fully
140replace a standard check function (or even a custom check function from
141another module). A module modifying checking must instead B<wrap> the
142preexisting check function. A custom check function must be selective
143about when to apply its custom behaviour. In the usual case where
144it decides not to do anything special with an op, it must chain the
145preexisting op function. Check functions are thus linked in a chain,
146with the core's base checker at the end.
147
148For thread safety, modules should not write directly to this array.
149Instead, use the function L</wrap_op_checker>.
150
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151=for apidoc Amn|enum perl_phase|PL_phase
152
153A value that indicates the current Perl interpreter's phase. Possible values
154include C<PERL_PHASE_CONSTRUCT>, C<PERL_PHASE_START>, C<PERL_PHASE_CHECK>,
155C<PERL_PHASE_INIT>, C<PERL_PHASE_RUN>, C<PERL_PHASE_END>, and
156C<PERL_PHASE_DESTRUCT>.
157
158For example, the following determines whether the interpreter is in
159global destruction:
160
161 if (PL_phase == PERL_PHASE_DESTRUCT) {
162 // we are in global destruction
163 }
164
165C<PL_phase> was introduced in Perl 5.14; in prior perls you can use
166C<PL_dirty> (boolean) to determine whether the interpreter is in global
167destruction. (Use of C<PL_dirty> is discouraged since 5.14.)
168
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169=cut
170*/
171
172#if defined(USE_ITHREADS)
173PERLVAR(G, check_mutex, perl_mutex) /* Mutex for PL_check */
174#endif
27da23d5 175
f16dd614 176/* allocate a unique index to every module that calls MY_CXT_INIT */
27da23d5 177
f16dd614 178#ifdef PERL_IMPLICIT_CONTEXT
97aff369 179# ifdef USE_ITHREADS
115ff745 180PERLVAR(G, my_ctx_mutex, perl_mutex)
97aff369 181# endif
115ff745 182PERLVARI(G, my_cxt_index, int, 0)
f16dd614 183#endif
71ad1b0c 184
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185/* this is currently set without MUTEX protection, so keep it a type which
186 * can be set atomically (ie not a bit field) */
115ff745 187PERLVARI(G, veto_cleanup, int, FALSE) /* exit without cleanup */
c301d606 188
88e1f1a2 189/*
78342678 190=for apidoc AmnUx|Perl_keyword_plugin_t|PL_keyword_plugin
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191
192Function pointer, pointing at a function used to handle extended keywords.
193The function should be declared as
194
195 int keyword_plugin_function(pTHX_
196 char *keyword_ptr, STRLEN keyword_len,
197 OP **op_ptr)
198
199The function is called from the tokeniser, whenever a possible keyword
200is seen. C<keyword_ptr> points at the word in the parser's input
201buffer, and C<keyword_len> gives its length; it is not null-terminated.
202The function is expected to examine the word, and possibly other state
203such as L<%^H|perlvar/%^H>, to decide whether it wants to handle it
204as an extended keyword. If it does not, the function should return
205C<KEYWORD_PLUGIN_DECLINE>, and the normal parser process will continue.
206
207If the function wants to handle the keyword, it first must
208parse anything following the keyword that is part of the syntax
f0e67a1d 209introduced by the keyword. See L</Lexer interface> for details.
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210
211When a keyword is being handled, the plugin function must build
212a tree of C<OP> structures, representing the code that was parsed.
213The root of the tree must be stored in C<*op_ptr>. The function then
364f83bf 214returns a constant indicating the syntactic role of the construct that
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215it has parsed: C<KEYWORD_PLUGIN_STMT> if it is a complete statement, or
216C<KEYWORD_PLUGIN_EXPR> if it is an expression. Note that a statement
217construct cannot be used inside an expression (except via C<do BLOCK>
218and similar), and an expression is not a complete statement (it requires
219at least a terminating semicolon).
220
221When a keyword is handled, the plugin function may also have
222(compile-time) side effects. It may modify C<%^H>, define functions, and
223so on. Typically, if side effects are the main purpose of a handler,
224it does not wish to generate any ops to be included in the normal
225compilation. In this case it is still required to supply an op tree,
226but it suffices to generate a single null op.
227
228That's how the C<*PL_keyword_plugin> function needs to behave overall.
229Conventionally, however, one does not completely replace the existing
230handler function. Instead, take a copy of C<PL_keyword_plugin> before
231assigning your own function pointer to it. Your handler function should
232look for keywords that it is interested in and handle those. Where it
233is not interested, it should call the saved plugin function, passing on
234the arguments it received. Thus C<PL_keyword_plugin> actually points
235at a chain of handler functions, all of which have an opportunity to
236handle keywords, and only the last function in the chain (built into
237the Perl core) will normally return C<KEYWORD_PLUGIN_DECLINE>.
238
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239For thread safety, modules should not set this variable directly.
240Instead, use the function L</wrap_keyword_plugin>.
241
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242=cut
243*/
244
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245#if defined(USE_ITHREADS)
246PERLVAR(G, keyword_plugin_mutex, perl_mutex) /* Mutex for PL_keyword_plugin */
247#endif
115ff745 248PERLVARI(G, keyword_plugin, Perl_keyword_plugin_t, Perl_keyword_plugin_standard)
eeb6b841 249
5c64bffd 250PERLVARI(G, op_sequence, HV *, NULL) /* dump.c */
115ff745 251PERLVARI(G, op_seq, UV, 0) /* dump.c */
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252
253#ifdef USE_ITHREADS
115ff745 254PERLVAR(G, dollarzero_mutex, perl_mutex) /* Modifying $0 */
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255#endif
256
257/* Restricted hashes placeholder value.
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258 In theory, the contents are never used, only the address.
259 In practice, &PL_sv_placeholder is returned by some APIs, and the calling
260 code is checking SvOK(). */
261
115ff745 262PERLVAR(G, sv_placeholder, SV)
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263
264#if defined(MYMALLOC) && defined(USE_ITHREADS)
115ff745 265PERLVAR(G, malloc_mutex, perl_mutex) /* Mutex for malloc */
eeb6b841 266#endif
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267
268PERLVARI(G, hash_seed_set, bool, FALSE) /* perl.c */
6a5b4183 269PERLVARA(G, hash_seed, PERL_HASH_SEED_BYTES, unsigned char) /* perl.c and hv.h */
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270#if defined(PERL_HASH_STATE_BYTES)
271PERLVARA(G, hash_state, PERL_HASH_STATE_BYTES, unsigned char) /* perl.c and hv.h */
272#endif
273#if defined(PERL_USE_SINGLE_CHAR_HASH_CACHE)
274PERLVARA(G, hash_chars, (1+256) * sizeof(U32), unsigned char) /* perl.c and hv.h */
275#endif
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276
277/* The path separator can vary depending on whether we're running under DCL or
278 * a Unix shell.
279 */
280#ifdef __VMS
281PERLVAR(G, perllib_sep, char)
282#endif
744ebf52 283
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284/* Definitions of user-defined \p{} properties, as the subs that define them
285 * are only called once */
286PERLVARI(G, user_def_props, HV *, NULL)
287
8310e7fa 288#if defined(USE_ITHREADS)
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289PERLVAR(G, user_def_props_aTHX, PerlInterpreter *) /* aTHX that user_def_props
290 was defined in */
291PERLVAR(G, user_prop_mutex, perl_mutex) /* Mutex for manipulating
292 PL_user_defined_properties */
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293#endif
294
a3815e44 295/* these record the best way to perform certain IO operations while
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296 * atomically setting FD_CLOEXEC. On the first call, a probe is done
297 * and the result recorded for use by subsequent calls.
298 * In theory these variables aren't thread-safe, but the worst that can
299 * happen is that two treads will both do an initial probe
300 */
301PERLVARI(G, strategy_dup, int, 0) /* doio.c */
302PERLVARI(G, strategy_dup2, int, 0) /* doio.c */
303PERLVARI(G, strategy_open, int, 0) /* doio.c */
304PERLVARI(G, strategy_open3, int, 0) /* doio.c */
305PERLVARI(G, strategy_mkstemp, int, 0) /* doio.c */
306PERLVARI(G, strategy_socket, int, 0) /* doio.c */
307PERLVARI(G, strategy_accept, int, 0) /* doio.c */
308PERLVARI(G, strategy_pipe, int, 0) /* doio.c */
309PERLVARI(G, strategy_socketpair, int, 0) /* doio.c */
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310
311#ifdef PERL_IMPLICIT_CONTEXT
04912be7 312#endif