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 PERLVAR(G, env_mutex, perl_mutex) /* Mutex for accessing ENV */
108 PERLVAR(G, locale_mutex, perl_mutex) /* Mutex related to locale handling */
109 # ifndef USE_THREAD_SAFE_LOCALE
110 PERLVAR(G, lc_numeric_mutex, perl_mutex) /* Mutex for switching LC_NUMERIC */
114 #ifdef USE_POSIX_2008_LOCALE
115 PERLVAR(G, C_locale_obj, locale_t)
118 PERLVARI(G, watch_pvx, char *, NULL)
121 =for apidoc AmnU|Perl_check_t *|PL_check
123 Array, indexed by opcode, of functions that will be called for the "check"
124 phase of optree building during compilation of Perl code. For most (but
125 not all) types of op, once the op has been initially built and populated
126 with child ops it will be filtered through the check function referenced
127 by the appropriate element of this array. The new op is passed in as the
128 sole argument to the check function, and the check function returns the
129 completed op. The check function may (as the name suggests) check the op
130 for validity and signal errors. It may also initialise or modify parts of
131 the ops, or perform more radical surgery such as adding or removing child
132 ops, or even throw the op away and return a different op in its place.
134 This array of function pointers is a convenient place to hook into the
135 compilation process. An XS module can put its own custom check function
136 in place of any of the standard ones, to influence the compilation of a
137 particular type of op. However, a custom check function must never fully
138 replace a standard check function (or even a custom check function from
139 another module). A module modifying checking must instead B<wrap> the
140 preexisting check function. A custom check function must be selective
141 about when to apply its custom behaviour. In the usual case where
142 it decides not to do anything special with an op, it must chain the
143 preexisting op function. Check functions are thus linked in a chain,
144 with the core's base checker at the end.
146 For thread safety, modules should not write directly to this array.
147 Instead, use the function L</wrap_op_checker>.
149 =for apidoc Amn|enum perl_phase|PL_phase
151 A value that indicates the current Perl interpreter's phase. Possible values
152 include C<PERL_PHASE_CONSTRUCT>, C<PERL_PHASE_START>, C<PERL_PHASE_CHECK>,
153 C<PERL_PHASE_INIT>, C<PERL_PHASE_RUN>, C<PERL_PHASE_END>, and
154 C<PERL_PHASE_DESTRUCT>.
156 For example, the following determines whether the interpreter is in
159 if (PL_phase == PERL_PHASE_DESTRUCT) {
160 // we are in global destruction
163 C<PL_phase> was introduced in Perl 5.14; in prior perls you can use
164 C<PL_dirty> (boolean) to determine whether the interpreter is in global
165 destruction. (Use of C<PL_dirty> is discouraged since 5.14.)
170 #if defined(USE_ITHREADS)
171 PERLVAR(G, check_mutex, perl_mutex) /* Mutex for PL_check */
174 /* allocate a unique index to every module that calls MY_CXT_INIT */
176 #ifdef PERL_IMPLICIT_CONTEXT
178 PERLVAR(G, my_ctx_mutex, perl_mutex)
180 PERLVARI(G, my_cxt_index, int, 0)
183 /* this is currently set without MUTEX protection, so keep it a type which
184 * can be set atomically (ie not a bit field) */
185 PERLVARI(G, veto_cleanup, int, FALSE) /* exit without cleanup */
188 =for apidoc AmnUx|Perl_keyword_plugin_t|PL_keyword_plugin
190 Function pointer, pointing at a function used to handle extended keywords.
191 The function should be declared as
193 int keyword_plugin_function(pTHX_
194 char *keyword_ptr, STRLEN keyword_len,
197 The function is called from the tokeniser, whenever a possible keyword
198 is seen. C<keyword_ptr> points at the word in the parser's input
199 buffer, and C<keyword_len> gives its length; it is not null-terminated.
200 The function is expected to examine the word, and possibly other state
201 such as L<%^H|perlvar/%^H>, to decide whether it wants to handle it
202 as an extended keyword. If it does not, the function should return
203 C<KEYWORD_PLUGIN_DECLINE>, and the normal parser process will continue.
205 If the function wants to handle the keyword, it first must
206 parse anything following the keyword that is part of the syntax
207 introduced by the keyword. See L</Lexer interface> for details.
209 When a keyword is being handled, the plugin function must build
210 a tree of C<OP> structures, representing the code that was parsed.
211 The root of the tree must be stored in C<*op_ptr>. The function then
212 returns a constant indicating the syntactic role of the construct that
213 it has parsed: C<KEYWORD_PLUGIN_STMT> if it is a complete statement, or
214 C<KEYWORD_PLUGIN_EXPR> if it is an expression. Note that a statement
215 construct cannot be used inside an expression (except via C<do BLOCK>
216 and similar), and an expression is not a complete statement (it requires
217 at least a terminating semicolon).
219 When a keyword is handled, the plugin function may also have
220 (compile-time) side effects. It may modify C<%^H>, define functions, and
221 so on. Typically, if side effects are the main purpose of a handler,
222 it does not wish to generate any ops to be included in the normal
223 compilation. In this case it is still required to supply an op tree,
224 but it suffices to generate a single null op.
226 That's how the C<*PL_keyword_plugin> function needs to behave overall.
227 Conventionally, however, one does not completely replace the existing
228 handler function. Instead, take a copy of C<PL_keyword_plugin> before
229 assigning your own function pointer to it. Your handler function should
230 look for keywords that it is interested in and handle those. Where it
231 is not interested, it should call the saved plugin function, passing on
232 the arguments it received. Thus C<PL_keyword_plugin> actually points
233 at a chain of handler functions, all of which have an opportunity to
234 handle keywords, and only the last function in the chain (built into
235 the Perl core) will normally return C<KEYWORD_PLUGIN_DECLINE>.
237 For thread safety, modules should not set this variable directly.
238 Instead, use the function L</wrap_keyword_plugin>.
243 #if defined(USE_ITHREADS)
244 PERLVAR(G, keyword_plugin_mutex, perl_mutex) /* Mutex for PL_keyword_plugin */
246 PERLVARI(G, keyword_plugin, Perl_keyword_plugin_t, Perl_keyword_plugin_standard)
248 PERLVARI(G, op_sequence, HV *, NULL) /* dump.c */
249 PERLVARI(G, op_seq, UV, 0) /* dump.c */
252 PERLVAR(G, dollarzero_mutex, perl_mutex) /* Modifying $0 */
255 /* Restricted hashes placeholder value.
256 In theory, the contents are never used, only the address.
257 In practice, &PL_sv_placeholder is returned by some APIs, and the calling
258 code is checking SvOK(). */
260 PERLVAR(G, sv_placeholder, SV)
262 #if defined(MYMALLOC) && defined(USE_ITHREADS)
263 PERLVAR(G, malloc_mutex, perl_mutex) /* Mutex for malloc */
266 PERLVARI(G, hash_seed_set, bool, FALSE) /* perl.c */
267 PERLVARA(G, hash_seed, PERL_HASH_SEED_BYTES, unsigned char) /* perl.c and hv.h */
268 #if defined(PERL_HASH_STATE_BYTES)
269 PERLVARA(G, hash_state, PERL_HASH_STATE_BYTES, unsigned char) /* perl.c and hv.h */
271 #if defined(PERL_USE_SINGLE_CHAR_HASH_CACHE)
272 PERLVARA(G, hash_chars, (1+256) * sizeof(U32), unsigned char) /* perl.c and hv.h */
275 /* The path separator can vary depending on whether we're running under DCL or
279 PERLVAR(G, perllib_sep, char)
282 /* Definitions of user-defined \p{} properties, as the subs that define them
283 * are only called once */
284 PERLVARI(G, user_def_props, HV *, NULL)
286 #if defined(USE_ITHREADS)
287 PERLVAR(G, user_def_props_aTHX, PerlInterpreter *) /* aTHX that user_def_props
289 PERLVAR(G, user_prop_mutex, perl_mutex) /* Mutex for manipulating
290 PL_user_defined_properties */
293 /* these record the best way to perform certain IO operations while
294 * atomically setting FD_CLOEXEC. On the first call, a probe is done
295 * and the result recorded for use by subsequent calls.
296 * In theory these variables aren't thread-safe, but the worst that can
297 * happen is that two treads will both do an initial probe
299 PERLVARI(G, strategy_dup, int, 0) /* doio.c */
300 PERLVARI(G, strategy_dup2, int, 0) /* doio.c */
301 PERLVARI(G, strategy_open, int, 0) /* doio.c */
302 PERLVARI(G, strategy_open3, int, 0) /* doio.c */
303 PERLVARI(G, strategy_mkstemp, int, 0) /* doio.c */
304 PERLVARI(G, strategy_socket, int, 0) /* doio.c */
305 PERLVARI(G, strategy_accept, int, 0) /* doio.c */
306 PERLVARI(G, strategy_pipe, int, 0) /* doio.c */
307 PERLVARI(G, strategy_socketpair, int, 0) /* doio.c */