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 PERLVAR(G, locale_mutex, perl_mutex) /* Mutex for setlocale() changing */
103 PERLVAR(G, lc_numeric_mutex, perl_mutex) /* Mutex for switching LC_NUMERIC */
107 /* Proxy for HAS_POSIX_2008_LOCALE, since that is not defined in time for this */
108 #if defined(HAS_NEWLOCALE) \
109 && defined(HAS_FREELOCALE) \
110 && defined(HAS_USELOCALE) \
111 && ! defined(NO_POSIX_2008_LOCALE)
112 PERLVAR(G, C_locale_obj, locale_t)
116 PERLVARI(G, watch_pvx, char *, NULL)
120 =for apidoc AmU|Perl_check_t *|PL_check
122 Array, indexed by opcode, of functions that will be called for the "check"
123 phase of optree building during compilation of Perl code. For most (but
124 not all) types of op, once the op has been initially built and populated
125 with child ops it will be filtered through the check function referenced
126 by the appropriate element of this array. The new op is passed in as the
127 sole argument to the check function, and the check function returns the
128 completed op. The check function may (as the name suggests) check the op
129 for validity and signal errors. It may also initialise or modify parts of
130 the ops, or perform more radical surgery such as adding or removing child
131 ops, or even throw the op away and return a different op in its place.
133 This array of function pointers is a convenient place to hook into the
134 compilation process. An XS module can put its own custom check function
135 in place of any of the standard ones, to influence the compilation of a
136 particular type of op. However, a custom check function must never fully
137 replace a standard check function (or even a custom check function from
138 another module). A module modifying checking must instead B<wrap> the
139 preexisting check function. A custom check function must be selective
140 about when to apply its custom behaviour. In the usual case where
141 it decides not to do anything special with an op, it must chain the
142 preexisting op function. Check functions are thus linked in a chain,
143 with the core's base checker at the end.
145 For thread safety, modules should not write directly to this array.
146 Instead, use the function L</wrap_op_checker>.
151 #if defined(USE_ITHREADS)
152 PERLVAR(G, check_mutex, perl_mutex) /* Mutex for PL_check */
154 #ifdef PERL_GLOBAL_STRUCT
155 PERLVAR(G, ppaddr, Perl_ppaddr_t *) /* or opcode.h */
156 PERLVAR(G, check, Perl_check_t *) /* or opcode.h */
157 PERLVARA(G, fold_locale, 256, unsigned char) /* or perl.h */
160 #ifdef PERL_NEED_APPCTX
161 PERLVAR(G, appctx, void*) /* the application context */
164 #if defined(HAS_TIMES) && defined(PERL_NEED_TIMESBASE)
165 PERLVAR(G, timesbase, struct tms)
168 /* allocate a unique index to every module that calls MY_CXT_INIT */
170 #ifdef PERL_IMPLICIT_CONTEXT
172 PERLVAR(G, my_ctx_mutex, perl_mutex)
174 PERLVARI(G, my_cxt_index, int, 0)
177 /* this is currently set without MUTEX protection, so keep it a type which
178 * can be set atomically (ie not a bit field) */
179 PERLVARI(G, veto_cleanup, int, FALSE) /* exit without cleanup */
182 =for apidoc AmUx|Perl_keyword_plugin_t|PL_keyword_plugin
184 Function pointer, pointing at a function used to handle extended keywords.
185 The function should be declared as
187 int keyword_plugin_function(pTHX_
188 char *keyword_ptr, STRLEN keyword_len,
191 The function is called from the tokeniser, whenever a possible keyword
192 is seen. C<keyword_ptr> points at the word in the parser's input
193 buffer, and C<keyword_len> gives its length; it is not null-terminated.
194 The function is expected to examine the word, and possibly other state
195 such as L<%^H|perlvar/%^H>, to decide whether it wants to handle it
196 as an extended keyword. If it does not, the function should return
197 C<KEYWORD_PLUGIN_DECLINE>, and the normal parser process will continue.
199 If the function wants to handle the keyword, it first must
200 parse anything following the keyword that is part of the syntax
201 introduced by the keyword. See L</Lexer interface> for details.
203 When a keyword is being handled, the plugin function must build
204 a tree of C<OP> structures, representing the code that was parsed.
205 The root of the tree must be stored in C<*op_ptr>. The function then
206 returns a constant indicating the syntactic role of the construct that
207 it has parsed: C<KEYWORD_PLUGIN_STMT> if it is a complete statement, or
208 C<KEYWORD_PLUGIN_EXPR> if it is an expression. Note that a statement
209 construct cannot be used inside an expression (except via C<do BLOCK>
210 and similar), and an expression is not a complete statement (it requires
211 at least a terminating semicolon).
213 When a keyword is handled, the plugin function may also have
214 (compile-time) side effects. It may modify C<%^H>, define functions, and
215 so on. Typically, if side effects are the main purpose of a handler,
216 it does not wish to generate any ops to be included in the normal
217 compilation. In this case it is still required to supply an op tree,
218 but it suffices to generate a single null op.
220 That's how the C<*PL_keyword_plugin> function needs to behave overall.
221 Conventionally, however, one does not completely replace the existing
222 handler function. Instead, take a copy of C<PL_keyword_plugin> before
223 assigning your own function pointer to it. Your handler function should
224 look for keywords that it is interested in and handle those. Where it
225 is not interested, it should call the saved plugin function, passing on
226 the arguments it received. Thus C<PL_keyword_plugin> actually points
227 at a chain of handler functions, all of which have an opportunity to
228 handle keywords, and only the last function in the chain (built into
229 the Perl core) will normally return C<KEYWORD_PLUGIN_DECLINE>.
231 For thread safety, modules should not set this variable directly.
232 Instead, use the function L</wrap_keyword_plugin>.
237 #if defined(USE_ITHREADS)
238 PERLVAR(G, keyword_plugin_mutex, perl_mutex) /* Mutex for PL_keyword_plugin */
240 PERLVARI(G, keyword_plugin, Perl_keyword_plugin_t, Perl_keyword_plugin_standard)
242 PERLVARI(G, op_sequence, HV *, NULL) /* dump.c */
243 PERLVARI(G, op_seq, UV, 0) /* dump.c */
246 PERLVAR(G, dollarzero_mutex, perl_mutex) /* Modifying $0 */
249 /* Restricted hashes placeholder value.
250 In theory, the contents are never used, only the address.
251 In practice, &PL_sv_placeholder is returned by some APIs, and the calling
252 code is checking SvOK(). */
254 PERLVAR(G, sv_placeholder, SV)
256 #if defined(MYMALLOC) && defined(USE_ITHREADS)
257 PERLVAR(G, malloc_mutex, perl_mutex) /* Mutex for malloc */
260 PERLVARI(G, hash_seed_set, bool, FALSE) /* perl.c */
261 PERLVARA(G, hash_seed, PERL_HASH_SEED_BYTES, unsigned char) /* perl.c and hv.h */
262 #if defined(PERL_HASH_STATE_BYTES)
263 PERLVARA(G, hash_state, PERL_HASH_STATE_BYTES, unsigned char) /* perl.c and hv.h */
265 #if defined(PERL_USE_SINGLE_CHAR_HASH_CACHE)
266 PERLVARA(G, hash_chars, (1+256) * sizeof(U32), unsigned char) /* perl.c and hv.h */
269 /* The path separator can vary depending on whether we're running under DCL or
273 PERLVAR(G, perllib_sep, char)