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