3 * Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
4 * by Larry Wall and others
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.
12 =head1 Global Variables
13 These variables are global to an entire process. They are shared between
14 all interpreters and all threads in a process. Any variables not documented
15 here may be changed or removed without notice, so don't use them!
16 If you feel you really do need to use an unlisted variable, first send email to
17 L<perl5-porters@perl.org|mailto:perl5-porters@perl.org>. It may be that
18 someone there will point out a way to accomplish what you need without using an
19 internal variable. But if not, you should get a go-ahead to document and then
25 /* Don't forget to re-run regen/embed.pl to propagate changes! */
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.
32 * The 'G' prefix is only needed for vars that need appropriate #defines
33 * generated in embed*.h. Such symbols are also used to generate
34 * the appropriate export list for win32. */
37 #if defined(USE_ITHREADS)
38 PERLVAR(G, op_mutex, perl_mutex) /* Mutex for op refcounting */
40 PERLVARI(G, curinterp, PerlInterpreter *, NULL)
41 /* currently running interpreter
42 * (initial parent interpreter under
44 #if defined(USE_ITHREADS)
45 PERLVAR(G, thr_key, perl_key) /* key to retrieve per-thread struct */
48 /* XXX does anyone even use this? */
49 PERLVARI(G, do_undump, bool, FALSE) /* -u or dump seen? */
51 #ifndef PERL_USE_SAFE_PUTENV
52 PERLVARI(G, use_safe_putenv, bool, TRUE)
55 #if defined(FAKE_PERSISTENT_SIGNAL_HANDLERS)||defined(FAKE_DEFAULT_SIGNAL_HANDLERS)
56 PERLVARI(G, sig_handlers_initted, int, 0)
58 #ifdef FAKE_PERSISTENT_SIGNAL_HANDLERS
59 PERLVARA(G, sig_ignoring, SIG_SIZE, int)
60 /* which signals we are ignoring */
62 #ifdef FAKE_DEFAULT_SIGNAL_HANDLERS
63 PERLVARA(G, sig_defaulting, SIG_SIZE, int)
66 /* XXX signals are process-wide anyway, so we
67 * ignore the implications of this for threading */
69 PERLVARI(G, sig_trapped, int, 0)
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. */
75 PERLVAR(G, sigfpe_saved, Sighandler_t)
77 /* these ptrs to functions are to avoid linkage problems; see
78 * perl-5.8.0-2193-g5c1546dc48
80 PERLVARI(G, csighandlerp, Sighandler_t, Perl_csighandler)
81 PERLVARI(G, csighandler1p, Sighandler1_t, Perl_csighandler1)
82 PERLVARI(G, csighandler3p, Sighandler3_t, Perl_csighandler3)
85 /* This is constant on most architectures, a global on OS/2 */
87 PERLVARI(G, sh_path, char *, SH_PATH) /* full path of shell */
92 # if defined(USE_ITHREADS)
93 PERLVAR(G, perlio_mutex, perl_mutex) /* Mutex for perlio fd refcounts */
96 PERLVARI(G, perlio_fd_refcnt, int *, 0) /* Pointer to array of fd refcounts. */
97 PERLVARI(G, perlio_fd_refcnt_size, int, 0) /* Size of the array */
98 PERLVARI(G, perlio_debug_fd, int, 0) /* the fd to write perlio debug into, 0 means not set yet */
102 PERLVARI(G, mmap_page_size, IV, 0)
105 #if defined(USE_ITHREADS)
106 PERLVAR(G, hints_mutex, perl_mutex) /* Mutex for refcounted he refcounting */
107 # if ! defined(USE_THREAD_SAFE_LOCALE) || defined(TS_W32_BROKEN_LOCALECONV)
108 PERLVAR(G, locale_mutex, perl_mutex) /* Mutex for setlocale() changing */
110 # ifndef USE_THREAD_SAFE_LOCALE
111 PERLVAR(G, lc_numeric_mutex, perl_mutex) /* Mutex for switching LC_NUMERIC */
115 #ifdef USE_POSIX_2008_LOCALE
116 PERLVAR(G, C_locale_obj, locale_t)
119 PERLVARI(G, watch_pvx, char *, NULL)
122 =for apidoc AmnU|Perl_check_t *|PL_check
124 Array, indexed by opcode, of functions that will be called for the "check"
125 phase of optree building during compilation of Perl code. For most (but
126 not all) types of op, once the op has been initially built and populated
127 with child ops it will be filtered through the check function referenced
128 by the appropriate element of this array. The new op is passed in as the
129 sole argument to the check function, and the check function returns the
130 completed op. The check function may (as the name suggests) check the op
131 for validity and signal errors. It may also initialise or modify parts of
132 the ops, or perform more radical surgery such as adding or removing child
133 ops, or even throw the op away and return a different op in its place.
135 This array of function pointers is a convenient place to hook into the
136 compilation process. An XS module can put its own custom check function
137 in place of any of the standard ones, to influence the compilation of a
138 particular type of op. However, a custom check function must never fully
139 replace a standard check function (or even a custom check function from
140 another module). A module modifying checking must instead B<wrap> the
141 preexisting check function. A custom check function must be selective
142 about when to apply its custom behaviour. In the usual case where
143 it decides not to do anything special with an op, it must chain the
144 preexisting op function. Check functions are thus linked in a chain,
145 with the core's base checker at the end.
147 For thread safety, modules should not write directly to this array.
148 Instead, use the function L</wrap_op_checker>.
150 =for apidoc Amn|enum perl_phase|PL_phase
152 A value that indicates the current Perl interpreter's phase. Possible values
153 include C<PERL_PHASE_CONSTRUCT>, C<PERL_PHASE_START>, C<PERL_PHASE_CHECK>,
154 C<PERL_PHASE_INIT>, C<PERL_PHASE_RUN>, C<PERL_PHASE_END>, and
155 C<PERL_PHASE_DESTRUCT>.
157 For example, the following determines whether the interpreter is in
160 if (PL_phase == PERL_PHASE_DESTRUCT) {
161 // we are in global destruction
164 C<PL_phase> was introduced in Perl 5.14; in prior perls you can use
165 C<PL_dirty> (boolean) to determine whether the interpreter is in global
166 destruction. (Use of C<PL_dirty> is discouraged since 5.14.)
171 #if defined(USE_ITHREADS)
172 PERLVAR(G, check_mutex, perl_mutex) /* Mutex for PL_check */
174 #ifdef PERL_GLOBAL_STRUCT
175 PERLVAR(G, ppaddr, Perl_ppaddr_t *) /* or opcode.h */
176 PERLVAR(G, check, Perl_check_t *) /* or opcode.h */
177 PERLVARA(G, fold_locale, 256, unsigned char) /* or perl.h */
180 #ifdef PERL_NEED_APPCTX
181 PERLVAR(G, appctx, void*) /* the application context */
184 #if defined(HAS_TIMES) && defined(PERL_NEED_TIMESBASE)
185 PERLVAR(G, timesbase, struct tms)
188 /* allocate a unique index to every module that calls MY_CXT_INIT */
190 #ifdef PERL_IMPLICIT_CONTEXT
192 PERLVAR(G, my_ctx_mutex, perl_mutex)
194 PERLVARI(G, my_cxt_index, int, 0)
197 /* this is currently set without MUTEX protection, so keep it a type which
198 * can be set atomically (ie not a bit field) */
199 PERLVARI(G, veto_cleanup, int, FALSE) /* exit without cleanup */
202 =for apidoc AmnUx|Perl_keyword_plugin_t|PL_keyword_plugin
204 Function pointer, pointing at a function used to handle extended keywords.
205 The function should be declared as
207 int keyword_plugin_function(pTHX_
208 char *keyword_ptr, STRLEN keyword_len,
211 The function is called from the tokeniser, whenever a possible keyword
212 is seen. C<keyword_ptr> points at the word in the parser's input
213 buffer, and C<keyword_len> gives its length; it is not null-terminated.
214 The function is expected to examine the word, and possibly other state
215 such as L<%^H|perlvar/%^H>, to decide whether it wants to handle it
216 as an extended keyword. If it does not, the function should return
217 C<KEYWORD_PLUGIN_DECLINE>, and the normal parser process will continue.
219 If the function wants to handle the keyword, it first must
220 parse anything following the keyword that is part of the syntax
221 introduced by the keyword. See L</Lexer interface> for details.
223 When a keyword is being handled, the plugin function must build
224 a tree of C<OP> structures, representing the code that was parsed.
225 The root of the tree must be stored in C<*op_ptr>. The function then
226 returns a constant indicating the syntactic role of the construct that
227 it has parsed: C<KEYWORD_PLUGIN_STMT> if it is a complete statement, or
228 C<KEYWORD_PLUGIN_EXPR> if it is an expression. Note that a statement
229 construct cannot be used inside an expression (except via C<do BLOCK>
230 and similar), and an expression is not a complete statement (it requires
231 at least a terminating semicolon).
233 When a keyword is handled, the plugin function may also have
234 (compile-time) side effects. It may modify C<%^H>, define functions, and
235 so on. Typically, if side effects are the main purpose of a handler,
236 it does not wish to generate any ops to be included in the normal
237 compilation. In this case it is still required to supply an op tree,
238 but it suffices to generate a single null op.
240 That's how the C<*PL_keyword_plugin> function needs to behave overall.
241 Conventionally, however, one does not completely replace the existing
242 handler function. Instead, take a copy of C<PL_keyword_plugin> before
243 assigning your own function pointer to it. Your handler function should
244 look for keywords that it is interested in and handle those. Where it
245 is not interested, it should call the saved plugin function, passing on
246 the arguments it received. Thus C<PL_keyword_plugin> actually points
247 at a chain of handler functions, all of which have an opportunity to
248 handle keywords, and only the last function in the chain (built into
249 the Perl core) will normally return C<KEYWORD_PLUGIN_DECLINE>.
251 For thread safety, modules should not set this variable directly.
252 Instead, use the function L</wrap_keyword_plugin>.
257 #if defined(USE_ITHREADS)
258 PERLVAR(G, keyword_plugin_mutex, perl_mutex) /* Mutex for PL_keyword_plugin */
260 PERLVARI(G, keyword_plugin, Perl_keyword_plugin_t, Perl_keyword_plugin_standard)
262 PERLVARI(G, op_sequence, HV *, NULL) /* dump.c */
263 PERLVARI(G, op_seq, UV, 0) /* dump.c */
266 PERLVAR(G, dollarzero_mutex, perl_mutex) /* Modifying $0 */
269 /* Restricted hashes placeholder value.
270 In theory, the contents are never used, only the address.
271 In practice, &PL_sv_placeholder is returned by some APIs, and the calling
272 code is checking SvOK(). */
274 PERLVAR(G, sv_placeholder, SV)
276 #if defined(MYMALLOC) && defined(USE_ITHREADS)
277 PERLVAR(G, malloc_mutex, perl_mutex) /* Mutex for malloc */
280 PERLVARI(G, hash_seed_set, bool, FALSE) /* perl.c */
281 PERLVARA(G, hash_seed, PERL_HASH_SEED_BYTES, unsigned char) /* perl.c and hv.h */
282 #if defined(PERL_HASH_STATE_BYTES)
283 PERLVARA(G, hash_state, PERL_HASH_STATE_BYTES, unsigned char) /* perl.c and hv.h */
285 #if defined(PERL_USE_SINGLE_CHAR_HASH_CACHE)
286 PERLVARA(G, hash_chars, (1+256) * sizeof(U32), unsigned char) /* perl.c and hv.h */
289 /* The path separator can vary depending on whether we're running under DCL or
293 PERLVAR(G, perllib_sep, char)
296 /* Definitions of user-defined \p{} properties, as the subs that define them
297 * are only called once */
298 PERLVARI(G, user_def_props, HV *, NULL)
300 #if defined(USE_ITHREADS)
301 PERLVAR(G, user_def_props_aTHX, PerlInterpreter *) /* aTHX that user_def_props
303 PERLVAR(G, user_prop_mutex, perl_mutex) /* Mutex for manipulating
304 PL_user_defined_properties */
307 /* Everything that folds to a given character, for case insensitivity regex
309 PERLVAR(G, utf8_foldclosures, SV *)
311 /* these record the best way to to perform certain IO operations while
312 * atomically setting FD_CLOEXEC. On the first call, a probe is done
313 * and the result recorded for use by subsequent calls.
314 * In theory these variables aren't thread-safe, but the worst that can
315 * happen is that two treads will both do an initial probe
317 PERLVARI(G, strategy_dup, int, 0) /* doio.c */
318 PERLVARI(G, strategy_dup2, int, 0) /* doio.c */
319 PERLVARI(G, strategy_open, int, 0) /* doio.c */
320 PERLVARI(G, strategy_open3, int, 0) /* doio.c */
321 PERLVARI(G, strategy_mkstemp, int, 0) /* doio.c */
322 PERLVARI(G, strategy_socket, int, 0) /* doio.c */
323 PERLVARI(G, strategy_accept, int, 0) /* doio.c */
324 PERLVARI(G, strategy_pipe, int, 0) /* doio.c */
325 PERLVARI(G, strategy_socketpair, int, 0) /* doio.c */
327 #ifdef PERL_IMPLICIT_CONTEXT
328 # ifdef PERL_GLOBAL_STRUCT_PRIVATE
329 /* per-module array of pointers to MY_CXT_KEY constants.
330 * It simulates each module having a static my_cxt_index var on builds
331 * which don't allow static vars */
332 PERLVARI(G, my_cxt_keys, const char **, NULL)
333 PERLVARI(G, my_cxt_keys_size, int, 0) /* size of PL_my_cxt_keys */