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)
76 PERLVARI(G, csighandlerp, Sighandler_t, Perl_csighandler)
77 /* Pointer to C-level sighandler */
80 /* This is constant on most architectures, a global on OS/2 */
82 PERLVARI(G, sh_path, char *, SH_PATH) /* full path of shell */
87 # if defined(USE_ITHREADS)
88 PERLVAR(G, perlio_mutex, perl_mutex) /* Mutex for perlio fd refcounts */
91 PERLVARI(G, perlio_fd_refcnt, int *, 0) /* Pointer to array of fd refcounts. */
92 PERLVARI(G, perlio_fd_refcnt_size, int, 0) /* Size of the array */
93 PERLVARI(G, perlio_debug_fd, int, 0) /* the fd to write perlio debug into, 0 means not set yet */
97 PERLVARI(G, mmap_page_size, IV, 0)
100 #if defined(USE_ITHREADS)
101 PERLVAR(G, hints_mutex, perl_mutex) /* Mutex for refcounted he refcounting */
102 #ifndef USE_THREAD_SAFE_LOCALE
103 PERLVAR(G, locale_mutex, perl_mutex) /* Mutex for setlocale() changing */
104 PERLVAR(G, lc_numeric_mutex, perl_mutex) /* Mutex for switching LC_NUMERIC */
108 /* Proxy for HAS_POSIX_2008_LOCALE, since that is not defined in time for this */
109 #if defined(HAS_NEWLOCALE) \
110 && defined(HAS_FREELOCALE) \
111 && defined(HAS_USELOCALE) \
112 && ! defined(NO_POSIX_2008_LOCALE)
113 PERLVAR(G, C_locale_obj, locale_t)
117 PERLVARI(G, watch_pvx, char *, NULL)
121 =for apidoc AmU|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>.
152 #if defined(USE_ITHREADS)
153 PERLVAR(G, check_mutex, perl_mutex) /* Mutex for PL_check */
155 #ifdef PERL_GLOBAL_STRUCT
156 PERLVAR(G, ppaddr, Perl_ppaddr_t *) /* or opcode.h */
157 PERLVAR(G, check, Perl_check_t *) /* or opcode.h */
158 PERLVARA(G, fold_locale, 256, unsigned char) /* or perl.h */
161 #ifdef PERL_NEED_APPCTX
162 PERLVAR(G, appctx, void*) /* the application context */
165 #if defined(HAS_TIMES) && defined(PERL_NEED_TIMESBASE)
166 PERLVAR(G, timesbase, struct tms)
169 /* allocate a unique index to every module that calls MY_CXT_INIT */
171 #ifdef PERL_IMPLICIT_CONTEXT
173 PERLVAR(G, my_ctx_mutex, perl_mutex)
175 PERLVARI(G, my_cxt_index, int, 0)
178 /* this is currently set without MUTEX protection, so keep it a type which
179 * can be set atomically (ie not a bit field) */
180 PERLVARI(G, veto_cleanup, int, FALSE) /* exit without cleanup */
183 =for apidoc AmUx|Perl_keyword_plugin_t|PL_keyword_plugin
185 Function pointer, pointing at a function used to handle extended keywords.
186 The function should be declared as
188 int keyword_plugin_function(pTHX_
189 char *keyword_ptr, STRLEN keyword_len,
192 The function is called from the tokeniser, whenever a possible keyword
193 is seen. C<keyword_ptr> points at the word in the parser's input
194 buffer, and C<keyword_len> gives its length; it is not null-terminated.
195 The function is expected to examine the word, and possibly other state
196 such as L<%^H|perlvar/%^H>, to decide whether it wants to handle it
197 as an extended keyword. If it does not, the function should return
198 C<KEYWORD_PLUGIN_DECLINE>, and the normal parser process will continue.
200 If the function wants to handle the keyword, it first must
201 parse anything following the keyword that is part of the syntax
202 introduced by the keyword. See L</Lexer interface> for details.
204 When a keyword is being handled, the plugin function must build
205 a tree of C<OP> structures, representing the code that was parsed.
206 The root of the tree must be stored in C<*op_ptr>. The function then
207 returns a constant indicating the syntactic role of the construct that
208 it has parsed: C<KEYWORD_PLUGIN_STMT> if it is a complete statement, or
209 C<KEYWORD_PLUGIN_EXPR> if it is an expression. Note that a statement
210 construct cannot be used inside an expression (except via C<do BLOCK>
211 and similar), and an expression is not a complete statement (it requires
212 at least a terminating semicolon).
214 When a keyword is handled, the plugin function may also have
215 (compile-time) side effects. It may modify C<%^H>, define functions, and
216 so on. Typically, if side effects are the main purpose of a handler,
217 it does not wish to generate any ops to be included in the normal
218 compilation. In this case it is still required to supply an op tree,
219 but it suffices to generate a single null op.
221 That's how the C<*PL_keyword_plugin> function needs to behave overall.
222 Conventionally, however, one does not completely replace the existing
223 handler function. Instead, take a copy of C<PL_keyword_plugin> before
224 assigning your own function pointer to it. Your handler function should
225 look for keywords that it is interested in and handle those. Where it
226 is not interested, it should call the saved plugin function, passing on
227 the arguments it received. Thus C<PL_keyword_plugin> actually points
228 at a chain of handler functions, all of which have an opportunity to
229 handle keywords, and only the last function in the chain (built into
230 the Perl core) will normally return C<KEYWORD_PLUGIN_DECLINE>.
232 For thread safety, modules should not set this variable directly.
233 Instead, use the function L</wrap_keyword_plugin>.
238 #if defined(USE_ITHREADS)
239 PERLVAR(G, keyword_plugin_mutex, perl_mutex) /* Mutex for PL_keyword_plugin */
241 PERLVARI(G, keyword_plugin, Perl_keyword_plugin_t, Perl_keyword_plugin_standard)
243 PERLVARI(G, op_sequence, HV *, NULL) /* dump.c */
244 PERLVARI(G, op_seq, UV, 0) /* dump.c */
247 PERLVAR(G, dollarzero_mutex, perl_mutex) /* Modifying $0 */
250 /* Restricted hashes placeholder value.
251 In theory, the contents are never used, only the address.
252 In practice, &PL_sv_placeholder is returned by some APIs, and the calling
253 code is checking SvOK(). */
255 PERLVAR(G, sv_placeholder, SV)
257 #if defined(MYMALLOC) && defined(USE_ITHREADS)
258 PERLVAR(G, malloc_mutex, perl_mutex) /* Mutex for malloc */
261 PERLVARI(G, hash_seed_set, bool, FALSE) /* perl.c */
262 PERLVARA(G, hash_seed, PERL_HASH_SEED_BYTES, unsigned char) /* perl.c and hv.h */
263 #if defined(PERL_HASH_STATE_BYTES)
264 PERLVARA(G, hash_state, PERL_HASH_STATE_BYTES, unsigned char) /* perl.c and hv.h */
266 #if defined(PERL_USE_SINGLE_CHAR_HASH_CACHE)
267 PERLVARA(G, hash_chars, (1+256) * sizeof(U32), unsigned char) /* perl.c and hv.h */
270 /* The path separator can vary depending on whether we're running under DCL or
274 PERLVAR(G, perllib_sep, char)