DESCRIPTION
This file is the autogenerated documentation of functions in the Perl interpreter that are documented using Perl's internal documentation format but are not marked as part of the Perl API. In other words, they are not for use in extensions!Compile-time scope hooks
- BhkENTRY
-
NOTE: this function is experimental and may change or be
removed without notice.
Return an entry from the BHK structure. which is a preprocessor token indicating which entry to return. If the appropriate flag is not set this will return NULL. The type of the return value depends on which entry you ask for.
void * BhkENTRY(BHK *hk, which)
- BhkFLAGS
-
NOTE: this function is experimental and may change or be
removed without notice.
Return the BHK's flags.
U32 BhkFLAGS(BHK *hk)
- CALL_BLOCK_HOOKS
-
NOTE: this function is experimental and may change or be
removed without notice.
Call all the registered block hooks for type which. which is a preprocessing token; the type of arg depends on which.
void CALL_BLOCK_HOOKS(which, arg)
Custom Operators
- core_prototype
-
This function assigns the prototype of the named core function to "sv", or
to a new mortal SV if "sv" is NULL. It returns the modified "sv", or
NULL if the core function has no prototype. "code" is a code as returned
by "keyword()". It must not be equal to 0.
SV * core_prototype(SV *sv, const char *name, const int code, int * const opnum)
CV Manipulation Functions
- docatch
-
Check for the cases 0 or 3 of cur_env.je_ret, only used inside an eval context.
0 is used as continue inside eval,
3 is used for a die caught by an inner eval - continue inner loop
See cop.h: je_mustcatch, when set at any runlevel to TRUE, means eval ops must establish a local jmpenv to handle exception traps.
OP* docatch(OP *o)
CV reference counts and CvOUTSIDE
- CvWEAKOUTSIDE
-
Each CV has a pointer, "CvOUTSIDE()", to its lexically enclosing
CV (if any). Because pointers to anonymous sub prototypes are
stored in "&" pad slots, it is a possible to get a circular reference,
with the parent pointing to the child and vice-versa. To avoid the
ensuing memory leak, we do not increment the reference count of the CV
pointed to by "CvOUTSIDE" in the one specific instance that the parent
has a "&" pad slot pointing back to us. In this case, we set the
"CvWEAKOUTSIDE" flag in the child. This allows us to determine under what
circumstances we should decrement the refcount of the parent when freeing
the child.
There is a further complication with non-closure anonymous subs (i.e. those that do not refer to any lexicals outside that sub). In this case, the anonymous prototype is shared rather than being cloned. This has the consequence that the parent may be freed while there are still active children, eg
BEGIN { $a = sub { eval '$x' } }
In this case, the BEGIN is freed immediately after execution since there are no active references to it: the anon sub prototype has "CvWEAKOUTSIDE" set since it's not a closure, and $a points to the same CV, so it doesn't contribute to BEGIN's refcount either. When $a is executed, the "eval '$x'" causes the chain of "CvOUTSIDE"s to be followed, and the freed BEGIN is accessed.
To avoid this, whenever a CV and its associated pad is freed, any "&" entries in the pad are explicitly removed from the pad, and if the refcount of the pointed-to anon sub is still positive, then that child's "CvOUTSIDE" is set to point to its grandparent. This will only occur in the single specific case of a non-closure anon prototype having one or more active references (such as $a above).
One other thing to consider is that a CV may be merely undefined rather than freed, eg "undef &foo". In this case, its refcount may not have reached zero, but we still delete its pad and its "CvROOT" etc. Since various children may still have their "CvOUTSIDE" pointing at this undefined CV, we keep its own "CvOUTSIDE" for the time being, so that the chain of lexical scopes is unbroken. For example, the following should print 123:
my $x = 123; sub tmp { sub { eval '$x' } } my $a = tmp(); undef &tmp; print $a->(); bool CvWEAKOUTSIDE(CV *cv)
Embedding Functions
- cv_dump
-
dump the contents of a CV
void cv_dump(CV *cv, const char *title)
- cv_forget_slab
-
When a CV has a reference count on its slab (CvSLABBED), it is responsible
for making sure it is freed. (Hence, no two CVs should ever have a
reference count on the same slab.) The CV only needs to reference the slab
during compilation. Once it is compiled and CvROOT attached, it has
finished its job, so it can forget the slab.
void cv_forget_slab(CV *cv)
- do_dump_pad
-
Dump the contents of a padlist
void do_dump_pad(I32 level, PerlIO *file, PADLIST *padlist, int full)
- padlist_dup
-
Duplicates a pad.
PADLIST * padlist_dup(PADLIST *srcpad, CLONE_PARAMS *param)
- padnamelist_dup
-
Duplicates a pad name list.
PADNAMELIST * padnamelist_dup(PADNAMELIST *srcpad, CLONE_PARAMS *param)
- padname_dup
-
Duplicates a pad name.
PADNAME * padname_dup(PADNAME *src, CLONE_PARAMS *param)
- pad_alloc_name
-
Allocates a place in the currently-compiling
pad (via ``pad_alloc'' in perlapi) and
then stores a name for that entry. name is adopted and
becomes the name entry; it must already contain the name
string. typestash and ourstash and the "padadd_STATE"
flag get added to name. None of the other
processing of ``pad_add_name_pvn'' in perlapi
is done. Returns the offset of the allocated pad slot.
PADOFFSET pad_alloc_name(PADNAME *name, U32 flags, HV *typestash, HV *ourstash)
- pad_block_start
-
Update the pad compilation state variables on entry to a new block.
void pad_block_start(int full)
- pad_check_dup
-
Check for duplicate declarations: report any of:
* a my in the current scope with the same name; * an our (anywhere in the pad) with the same name and the same stash as C<ourstash>
"is_our" indicates that the name to check is an 'our' declaration.
void pad_check_dup(PADNAME *name, U32 flags, const HV *ourstash)
- pad_findlex
-
Find a named lexical anywhere in a chain of nested pads. Add fake entries
in the inner pads if it's found in an outer one.
Returns the offset in the bottom pad of the lex or the fake lex. cv is the CV in which to start the search, and seq is the current cop_seq to match against. If warn is true, print appropriate warnings. The out_* vars return values, and so are pointers to where the returned values should be stored. out_capture, if non-null, requests that the innermost instance of the lexical is captured; out_name is set to the innermost matched pad name or fake pad name; out_flags returns the flags normally associated with the PARENT_FAKELEX_FLAGS field of a fake pad name.
Note that pad_findlex() is recursive; it recurses up the chain of CVs, then comes back down, adding fake entries as it goes. It has to be this way because fake names in anon protoypes have to store in xlow the index into the parent pad.
PADOFFSET pad_findlex(const char *namepv, STRLEN namelen, U32 flags, const CV* cv, U32 seq, int warn, SV** out_capture, PADNAME** out_name, int *out_flags)
- pad_fixup_inner_anons
-
For any anon CVs in the pad, change CvOUTSIDE of that CV from
old_cv to new_cv if necessary. Needed when a newly-compiled CV has to be
moved to a pre-existing CV struct.
void pad_fixup_inner_anons(PADLIST *padlist, CV *old_cv, CV *new_cv)
- pad_free
-
Free the SV at offset po in the current pad.
void pad_free(PADOFFSET po)
- pad_leavemy
-
Cleanup at end of scope during compilation: set the max seq number for
lexicals in this scope and warn of any lexicals that never got introduced.
void pad_leavemy()
- pad_push
-
Push a new pad frame onto the padlist, unless there's already a pad at
this depth, in which case don't bother creating a new one. Then give
the new pad an @_ in slot zero.
void pad_push(PADLIST *padlist, int depth)
- pad_reset
-
Mark all the current temporaries for reuse
void pad_reset()
- pad_swipe
-
Abandon the tmp in the current pad at offset po and replace with a
new one.
void pad_swipe(PADOFFSET po, bool refadjust)
GV Functions
- gv_try_downgrade
-
NOTE: this function is experimental and may change or be
removed without notice.
If the typeglob "gv" can be expressed more succinctly, by having something other than a real GV in its place in the stash, replace it with the optimised form. Basic requirements for this are that "gv" is a real typeglob, is sufficiently ordinary, and is only referenced from its package. This function is meant to be used when a GV has been looked up in part to see what was there, causing upgrading, but based on what was found it turns out that the real GV isn't required after all.
If "gv" is a completely empty typeglob, it is deleted from the stash.
If "gv" is a typeglob containing only a sufficiently-ordinary constant sub, the typeglob is replaced with a scalar-reference placeholder that more compactly represents the same thing.
void gv_try_downgrade(GV* gv)
Hash Manipulation Functions
- hv_ename_add
-
Adds a name to a stash's internal list of effective names. See
"hv_ename_delete".
This is called when a stash is assigned to a new location in the symbol table.
void hv_ename_add(HV *hv, const char *name, U32 len, U32 flags)
- hv_ename_delete
-
Removes a name from a stash's internal list of effective names. If this is
the name returned by "HvENAME", then another name in the list will take
its place ("HvENAME" will use it).
This is called when a stash is deleted from the symbol table.
void hv_ename_delete(HV *hv, const char *name, U32 len, U32 flags)
- refcounted_he_chain_2hv
-
Generates and returns a "HV *" representing the content of a
"refcounted_he" chain.
flags is currently unused and must be zero.
HV * refcounted_he_chain_2hv( const struct refcounted_he *c, U32 flags )
- refcounted_he_fetch_pv
-
Like ``refcounted_he_fetch_pvn'', but takes a nul-terminated string
instead of a string/length pair.
SV * refcounted_he_fetch_pv( const struct refcounted_he *chain, const char *key, U32 hash, U32 flags )
- refcounted_he_fetch_pvn
-
Search along a "refcounted_he" chain for an entry with the key specified
by keypv and keylen. If flags has the "REFCOUNTED_HE_KEY_UTF8"
bit set, the key octets are interpreted as UTF-8, otherwise they
are interpreted as Latin-1. hash is a precomputed hash of the key
string, or zero if it has not been precomputed. Returns a mortal scalar
representing the value associated with the key, or &PL_sv_placeholder
if there is no value associated with the key.
SV * refcounted_he_fetch_pvn( const struct refcounted_he *chain, const char *keypv, STRLEN keylen, U32 hash, U32 flags )
- refcounted_he_fetch_pvs
-
Like ``refcounted_he_fetch_pvn'', but takes a literal string instead of
a string/length pair, and no precomputed hash.
SV * refcounted_he_fetch_pvs( const struct refcounted_he *chain, const char *key, U32 flags )
- refcounted_he_fetch_sv
-
Like ``refcounted_he_fetch_pvn'', but takes a Perl scalar instead of a
string/length pair.
SV * refcounted_he_fetch_sv( const struct refcounted_he *chain, SV *key, U32 hash, U32 flags )
- refcounted_he_free
-
Decrements the reference count of a "refcounted_he" by one. If the
reference count reaches zero the structure's memory is freed, which
(recursively) causes a reduction of its parent "refcounted_he"'s
reference count. It is safe to pass a null pointer to this function:
no action occurs in this case.
void refcounted_he_free(struct refcounted_he *he)
- refcounted_he_inc
-
Increment the reference count of a "refcounted_he". The pointer to the
"refcounted_he" is also returned. It is safe to pass a null pointer
to this function: no action occurs and a null pointer is returned.
struct refcounted_he * refcounted_he_inc( struct refcounted_he *he )
- refcounted_he_new_pv
-
Like ``refcounted_he_new_pvn'', but takes a nul-terminated string instead
of a string/length pair.
struct refcounted_he * refcounted_he_new_pv( struct refcounted_he *parent, const char *key, U32 hash, SV *value, U32 flags )
- refcounted_he_new_pvn
-
Creates a new "refcounted_he". This consists of a single key/value
pair and a reference to an existing "refcounted_he" chain (which may
be empty), and thus forms a longer chain. When using the longer chain,
the new key/value pair takes precedence over any entry for the same key
further along the chain.
The new key is specified by keypv and keylen. If flags has the "REFCOUNTED_HE_KEY_UTF8" bit set, the key octets are interpreted as UTF-8, otherwise they are interpreted as Latin-1. hash is a precomputed hash of the key string, or zero if it has not been precomputed.
value is the scalar value to store for this key. value is copied by this function, which thus does not take ownership of any reference to it, and later changes to the scalar will not be reflected in the value visible in the "refcounted_he". Complex types of scalar will not be stored with referential integrity, but will be coerced to strings. value may be either null or &PL_sv_placeholder to indicate that no value is to be associated with the key; this, as with any non-null value, takes precedence over the existence of a value for the key further along the chain.
parent points to the rest of the "refcounted_he" chain to be attached to the new "refcounted_he". This function takes ownership of one reference to parent, and returns one reference to the new "refcounted_he".
struct refcounted_he * refcounted_he_new_pvn( struct refcounted_he *parent, const char *keypv, STRLEN keylen, U32 hash, SV *value, U32 flags )
- refcounted_he_new_pvs
-
Like ``refcounted_he_new_pvn'', but takes a literal string instead of
a string/length pair, and no precomputed hash.
struct refcounted_he * refcounted_he_new_pvs( struct refcounted_he *parent, const char *key, SV *value, U32 flags )
- refcounted_he_new_sv
-
Like ``refcounted_he_new_pvn'', but takes a Perl scalar instead of a
string/length pair.
struct refcounted_he * refcounted_he_new_sv( struct refcounted_he *parent, SV *key, U32 hash, SV *value, U32 flags )
IO Functions
- start_glob
-
NOTE: this function is experimental and may change or be
removed without notice.
Function called by "do_readline" to spawn a glob (or do the glob inside perl on VMS). This code used to be inline, but now perl uses "File::Glob" this glob starter is only used by miniperl during the build process. Moving it away shrinks pp_hot.c; shrinking pp_hot.c helps speed perl up.
PerlIO* start_glob(SV *tmpglob, IO *io)
Lexer interface
- validate_proto
-
NOTE: this function is experimental and may change or be
removed without notice.
This function performs syntax checking on a prototype, "proto". If "warn" is true, any illegal characters or mismatched brackets will trigger illegalproto warnings, declaring that they were detected in the prototype for "name".
The return value is "true" if this is a valid prototype, and "false" if it is not, regardless of whether "warn" was "true" or "false".
Note that "NULL" is a valid "proto" and will always return "true".
NOTE: the perl_ form of this function is deprecated.
bool validate_proto(SV *name, SV *proto, bool warn)
Magical Functions
- magic_clearhint
-
Triggered by a delete from %^H, records the key to
"PL_compiling.cop_hints_hash".
int magic_clearhint(SV* sv, MAGIC* mg)
- magic_clearhints
-
Triggered by clearing %^H, resets "PL_compiling.cop_hints_hash".
int magic_clearhints(SV* sv, MAGIC* mg)
- magic_methcall
-
Invoke a magic method (like FETCH).
"sv" and "mg" are the tied thingy and the tie magic.
"meth" is the name of the method to call.
"argc" is the number of args (in addition to $self) to pass to the method.
The "flags" can be:
G_DISCARD invoke method with G_DISCARD flag and don't return a value G_UNDEF_FILL fill the stack with argc pointers to PL_sv_undef
The arguments themselves are any values following the "flags" argument.
Returns the SV (if any) returned by the method, or NULL on failure.
SV* magic_methcall(SV *sv, const MAGIC *mg, SV *meth, U32 flags, U32 argc, ...)
- magic_sethint
-
Triggered by a store to %^H, records the key/value pair to
"PL_compiling.cop_hints_hash". It is assumed that hints aren't storing
anything that would need a deep copy. Maybe we should warn if we find a
reference.
int magic_sethint(SV* sv, MAGIC* mg)
- mg_localize
-
Copy some of the magic from an existing SV to new localized version of that
SV. Container magic (eg %ENV, $1, tie)
gets copied, value magic doesn't (eg
taint, pos).
If setmagic is false then no set magic will be called on the new (empty) SV. This typically means that assignment will soon follow (e.g. 'local $x = $y'), and that will handle the magic.
void mg_localize(SV* sv, SV* nsv, bool setmagic)
Miscellaneous Functions
- free_c_backtrace
-
Deallocates a backtrace received from get_c_bracktrace.
void free_c_backtrace(Perl_c_backtrace* bt)
- get_c_backtrace
-
Collects the backtrace (aka ``stacktrace'') into a single linear
malloced buffer, which the caller must Perl_free_c_backtrace().
Scans the frames back by depth + skip, then drops the skip innermost, returning at most depth frames.
Perl_c_backtrace* get_c_backtrace(int max_depth, int skip)
MRO Functions
- mro_get_linear_isa_dfs
-
Returns the Depth-First Search linearization of @ISA
the given stash. The return value is a read-only AV*.
"level" should be 0 (it is used internally in this
function's recursion).
You are responsible for "SvREFCNT_inc()" on the return value if you plan to store it anywhere semi-permanently (otherwise it might be deleted out from under you the next time the cache is invalidated).
AV* mro_get_linear_isa_dfs(HV* stash, U32 level)
- mro_isa_changed_in
-
Takes the necessary steps (cache invalidations, mostly)
when the @ISA of the given package has changed. Invoked
by the "setisa" magic, should not need to invoke directly.
void mro_isa_changed_in(HV* stash)
- mro_package_moved
-
Call this function to signal to a stash that it has been assigned to
another spot in the stash hierarchy. "stash" is the stash that has been
assigned. "oldstash" is the stash it replaces, if any. "gv" is the glob
that is actually being assigned to.
This can also be called with a null first argument to indicate that "oldstash" has been deleted.
This function invalidates isa caches on the old stash, on all subpackages nested inside it, and on the subclasses of all those, including non-existent packages that have corresponding entries in "stash".
It also sets the effective names ("HvENAME") on all the stashes as appropriate.
If the "gv" is present and is not in the symbol table, then this function simply returns. This checked will be skipped if "flags & 1".
void mro_package_moved(HV * const stash, HV * const oldstash, const GV * const gv, U32 flags)
Optree Manipulation Functions
- finalize_optree
-
This function finalizes the optree. Should be called directly after
the complete optree is built. It does some additional
checking which can't be done in the normal ck_xxx functions and makes
the tree thread-safe.
void finalize_optree(OP* o)
Pad Data Structures
- CX_CURPAD_SAVE
-
Save the current pad in the given context block structure.
void CX_CURPAD_SAVE(struct context)
- CX_CURPAD_SV
-
Access the SV at offset po in the saved current pad in the given
context block structure (can be used as an lvalue).
SV * CX_CURPAD_SV(struct context, PADOFFSET po)
- PadnameIsOUR
-
Whether this is an ``our'' variable.
bool PadnameIsOUR(PADNAME pn)
- PadnameIsSTATE
-
Whether this is a ``state'' variable.
bool PadnameIsSTATE(PADNAME pn)
- PadnameOURSTASH
-
The stash in which this ``our'' variable was declared.
HV * PadnameOURSTASH()
- PadnameOUTER
-
Whether this entry belongs to an outer pad. Entries for which this is true
are often referred to as 'fake'.
bool PadnameOUTER(PADNAME pn)
- PadnameTYPE
-
The stash associated with a typed lexical. This returns the %Foo:: hash
for "my Foo $bar".
HV * PadnameTYPE(PADNAME pn)
- PAD_BASE_SV
-
Get the value from slot "po" in the base (DEPTH=1) pad of a padlist
SV * PAD_BASE_SV(PADLIST padlist, PADOFFSET po)
- PAD_CLONE_VARS
-
Clone the state variables associated with running and compiling pads.
void PAD_CLONE_VARS(PerlInterpreter *proto_perl, CLONE_PARAMS* param)
- PAD_COMPNAME_FLAGS
-
Return the flags for the current compiling pad name
at offset "po". Assumes a valid slot entry.
U32 PAD_COMPNAME_FLAGS(PADOFFSET po)
- PAD_COMPNAME_GEN
-
The generation number of the name at offset "po" in the current
compiling pad (lvalue). Note that "SvUVX" is hijacked for this purpose.
STRLEN PAD_COMPNAME_GEN(PADOFFSET po)
- PAD_COMPNAME_GEN_set
-
Sets the generation number of the name at offset "po" in the current
ling pad (lvalue) to "gen". Note that "SvUV_set" is hijacked for this purpose.
STRLEN PAD_COMPNAME_GEN_set(PADOFFSET po, int gen)
- PAD_COMPNAME_OURSTASH
-
Return the stash associated with an "our" variable.
Assumes the slot entry is a valid "our" lexical.
HV * PAD_COMPNAME_OURSTASH(PADOFFSET po)
- PAD_COMPNAME_PV
-
Return the name of the current compiling pad name
at offset "po". Assumes a valid slot entry.
char * PAD_COMPNAME_PV(PADOFFSET po)
- PAD_COMPNAME_TYPE
-
Return the type (stash) of the current compiling pad name at offset
"po". Must be a valid name. Returns null if not typed.
HV * PAD_COMPNAME_TYPE(PADOFFSET po)
- PAD_RESTORE_LOCAL
-
Restore the old pad saved into the local variable opad by PAD_SAVE_LOCAL()
void PAD_RESTORE_LOCAL(PAD *opad)
- PAD_SAVE_LOCAL
-
Save the current pad to the local variable opad, then make the
current pad equal to npad
void PAD_SAVE_LOCAL(PAD *opad, PAD *npad)
- PAD_SAVE_SETNULLPAD
-
Save the current pad then set it to null.
void PAD_SAVE_SETNULLPAD()
- PAD_SETSV
-
Set the slot at offset "po" in the current pad to "sv"
SV * PAD_SETSV(PADOFFSET po, SV* sv)
- PAD_SET_CUR
-
Set the current pad to be pad "n" in the padlist, saving
the previous current pad. NB currently this macro expands to a string too
long for some compilers, so it's best to replace it with
SAVECOMPPAD(); PAD_SET_CUR_NOSAVE(padlist,n); void PAD_SET_CUR(PADLIST padlist, I32 n)
- PAD_SET_CUR_NOSAVE
-
like PAD_SET_CUR, but without the save
void PAD_SET_CUR_NOSAVE(PADLIST padlist, I32 n)
- PAD_SV
-
Get the value at offset "po" in the current pad
SV * PAD_SV(PADOFFSET po)
- PAD_SVl
-
Lightweight and lvalue version of "PAD_SV".
Get or set the value at offset "po" in the current pad.
Unlike "PAD_SV", does not print diagnostics with -DX.
For internal use only.
SV * PAD_SVl(PADOFFSET po)
- SAVECLEARSV
-
Clear the pointed to pad value on scope exit. (i.e. the runtime action of
'my')
void SAVECLEARSV(SV **svp)
- SAVECOMPPAD
-
save PL_comppad and PL_curpad
void SAVECOMPPAD()
- SAVEPADSV
-
Save a pad slot (used to restore after an iteration)
XXX DAPM it would make more sense to make the arg a PADOFFSET void SAVEPADSV(PADOFFSET po)
Per-Interpreter Variables
- PL_DBsingle
-
When Perl is run in debugging mode, with the -d switch, this SV is a
boolean which indicates whether subs are being single-stepped.
Single-stepping is automatically turned on after every step. This is the C
variable which corresponds to Perl's $DB::single variable. See
"PL_DBsub".
SV * PL_DBsingle
- PL_DBsub
-
When Perl is run in debugging mode, with the -d switch, this GV contains
the SV which holds the name of the sub being debugged. This is the C
variable which corresponds to Perl's $DB::sub variable. See
"PL_DBsingle".
GV * PL_DBsub
- PL_DBtrace
-
Trace variable used when Perl is run in debugging mode, with the -d
switch. This is the C variable which corresponds to Perl's $DB::trace
variable. See "PL_DBsingle".
SV * PL_DBtrace
- PL_dowarn
-
The C variable which corresponds to Perl's $^W warning variable.
bool PL_dowarn
- PL_last_in_gv
-
The GV which was last used for a filehandle input operation. ("<FH>")
GV* PL_last_in_gv
- PL_ofsgv
-
The glob containing the output field separator - "*," in Perl space.
GV* PL_ofsgv
- PL_rs
-
The input record separator - $/ in Perl space.
SV* PL_rs
Stack Manipulation Macros
- djSP
-
Declare Just "SP". This is actually identical to "dSP", and declares
a local copy of perl's stack pointer, available via the "SP" macro.
See "SP". (Available for backward source code compatibility with the
old (Perl 5.005) thread model.)
djSP;
- LVRET
- True if this op will be the return value of an lvalue subroutine
SV Manipulation Functions
An SV (or AV, HV, etc.) is allocated in two parts: the head (struct sv, av, hv...) contains type and reference count information, and for many types, a pointer to the body (struct xrv, xpv, xpviv...), which contains fields specific to each type. Some types store all they need in the head, so don't have a body.In all but the most memory-paranoid configurations (ex: PURIFY), heads and bodies are allocated out of arenas, which by default are approximately 4K chunks of memory parcelled up into N heads or bodies. Sv-bodies are allocated by their sv-type, guaranteeing size consistency needed to allocate safely from arrays.
For SV-heads, the first slot in each arena is reserved, and holds a link to the next arena, some flags, and a note of the number of slots. Snaked through each arena chain is a linked list of free items; when this becomes empty, an extra arena is allocated and divided up into N items which are threaded into the free list.
SV-bodies are similar, but they use arena-sets by default, which separate the link and info from the arena itself, and reclaim the 1st slot in the arena. SV-bodies are further described later.
The following global variables are associated with arenas:
PL_sv_arenaroot pointer to list of SV arenas PL_sv_root pointer to list of free SV structures PL_body_arenas head of linked-list of body arenas PL_body_roots[] array of pointers to list of free bodies of svtype arrays are indexed by the svtype needed
A few special SV heads are not allocated from an arena, but are instead directly created in the interpreter structure, eg PL_sv_undef. The size of arenas can be changed from the default by setting PERL_ARENA_SIZE appropriately at compile time.
The SV arena serves the secondary purpose of allowing still-live SVs to be located and destroyed during final cleanup.
At the lowest level, the macros new_SV() and del_SV() grab and free an SV head. (If debugging with -DD, del_SV() calls the function S_del_sv() to return the SV to the free list with error checking.) new_SV() calls more_sv() / sv_add_arena() to add an extra arena if the free list is empty. SVs in the free list have their SvTYPE field set to all ones.
At the time of very final cleanup, sv_free_arenas() is called from perl_destruct() to physically free all the arenas allocated since the start of the interpreter.
The function visit() scans the SV arenas list, and calls a specified function for each SV it finds which is still live - ie which has an SvTYPE other than all 1's, and a non-zero SvREFCNT. visit() is used by the following functions (specified as [function that calls visit()] / [function called by visit() for each SV]):
sv_report_used() / do_report_used() dump all remaining SVs (debugging aid) sv_clean_objs() / do_clean_objs(),do_clean_named_objs(), do_clean_named_io_objs(),do_curse() Attempt to free all objects pointed to by RVs, try to do the same for all objects indir- ectly referenced by typeglobs too, and then do a final sweep, cursing any objects that remain. Called once from perl_destruct(), prior to calling sv_clean_all() below. sv_clean_all() / do_clean_all() SvREFCNT_dec(sv) each remaining SV, possibly triggering an sv_free(). It also sets the SVf_BREAK flag on the SV to indicate that the refcnt has been artificially lowered, and thus stopping sv_free() from giving spurious warnings about SVs which unexpectedly have a refcnt of zero. called repeatedly from perl_destruct() until there are no SVs left.
- SvTHINKFIRST
-
A quick flag check to see whether an sv should be passed to sv_force_normal
to be ``downgraded'' before SvIVX or SvPVX can be modified directly.
For example, if your scalar is a reference and you want to modify the SvIVX slot, you can't just do SvROK_off, as that will leak the referent.
This is used internally by various sv-modifying functions, such as sv_setsv, sv_setiv and sv_pvn_force.
One case that this does not handle is a gv without SvFAKE set. After
if (SvTHINKFIRST(gv)) sv_force_normal(gv);
it will still be a gv.
SvTHINKFIRST sometimes produces false positives. In those cases sv_force_normal does nothing.
U32 SvTHINKFIRST(SV *sv)
- sv_add_arena
-
Given a chunk of memory, link it to the head of the list of arenas,
and split it into a list of free SVs.
void sv_add_arena(char *const ptr, const U32 size, const U32 flags)
- sv_clean_all
-
Decrement the refcnt of each remaining SV, possibly triggering a
cleanup. This function may have to be called multiple times to free
SVs which are in complex self-referential hierarchies.
I32 sv_clean_all()
- sv_clean_objs
-
Attempt to destroy all objects not yet freed.
void sv_clean_objs()
- sv_free_arenas
-
Deallocate the memory used by all arenas. Note that all the individual SV
heads and bodies within the arenas must already have been freed.
void sv_free_arenas()
SV-Body Allocation
- sv_2num
-
NOTE: this function is experimental and may change or be
removed without notice.
Return an SV with the numeric value of the source SV, doing any necessary reference or overload conversion. The caller is expected to have handled get-magic already.
SV* sv_2num(SV *const sv)
- sv_copypv
-
Copies a stringified representation of the source SV into the
destination SV. Automatically performs any necessary mg_get and
coercion of numeric values into strings. Guaranteed to preserve
UTF8 flag even from overloaded objects. Similar in nature to
sv_2pv[_flags] but operates directly on an SV instead of just the
string. Mostly uses sv_2pv_flags to do its work, except when that
would lose the UTF-8'ness of the PV.
void sv_copypv(SV *const dsv, SV *const ssv)
- sv_ref
-
Returns a SV describing what the SV passed in is a reference to.
SV* sv_ref(SV *dst, const SV *const sv, const int ob)
Unicode Support
- find_uninit_var
-
NOTE: this function is experimental and may change or be
removed without notice.
Find the name of the undefined variable (if any) that caused the operator to issue a ``Use of uninitialized value'' warning. If match is true, only return a name if its value matches uninit_sv. So roughly speaking, if a unary operator (such as OP_COS) generates a warning, then following the direct child of the op may yield an OP_PADSV or OP_GV that gives the name of the undefined variable. On the other hand, with OP_ADD there are two branches to follow, so we only print the variable name if we get an exact match. desc_p points to a string pointer holding the description of the op. This may be updated if needed.
The name is returned as a mortal SV.
Assumes that PL_op is the op that originally triggered the error, and that PL_comppad/PL_curpad points to the currently executing pad.
SV* find_uninit_var(const OP *const obase, const SV *const uninit_sv, bool match, const char **desc_p)
- report_uninit
-
Print appropriate ``Use of uninitialized variable'' warning.
void report_uninit(const SV *uninit_sv)
Undocumented functions
The following functions are currently undocumented. If you use one of them, you may wish to consider creating and submitting documentation for it.- PerlIO_restore_errno
- PerlIO_save_errno
- Slab_Alloc
- Slab_Free
- Slab_to_ro
- Slab_to_rw
- _add_range_to_invlist
- _core_swash_init
- _get_encoding
- _get_swash_invlist
- _invlist_array_init
- _invlist_contains_cp
- _invlist_contents
- _invlist_dump
- _invlist_intersection
- _invlist_intersection_maybe_complement_2nd
- _invlist_invert
- _invlist_len
- _invlist_populate_swatch
- _invlist_search
- _invlist_subtract
- _invlist_union
- _invlist_union_maybe_complement_2nd
- _load_PL_utf8_foldclosures
- _new_invlist
- _setup_canned_invlist
- _swash_inversion_hash
- _swash_to_invlist
- _to_fold_latin1
- _to_upper_title_latin1
- _warn_problematic_locale
- aassign_common_vars
- add_cp_to_invlist
- alloc_maybe_populate_EXACT
- allocmy
- amagic_is_enabled
- apply
- av_extend_guts
- av_reify
- bind_match
- boot_core_PerlIO
- boot_core_UNIVERSAL
- boot_core_mro
- cando
- check_utf8_print
- ck_anoncode
- ck_backtick
- ck_bitop
- ck_cmp
- ck_concat
- ck_defined
- ck_delete
- ck_each
- ck_entersub_args_core
- ck_eof
- ck_eval
- ck_exec
- ck_exists
- ck_ftst
- ck_fun
- ck_glob
- ck_grep
- ck_index
- ck_join
- ck_length
- ck_lfun
- ck_listiob
- ck_match
- ck_method
- ck_null
- ck_open
- ck_prototype
- ck_readline
- ck_refassign
- ck_repeat
- ck_require
- ck_return
- ck_rfun
- ck_rvconst
- ck_sassign
- ck_select
- ck_shift
- ck_smartmatch
- ck_sort
- ck_spair
- ck_split
- ck_stringify
- ck_subr
- ck_substr
- ck_svconst
- ck_tell
- ck_trunc
- closest_cop
- compute_EXACTish
- coresub_op
- create_eval_scope
- croak_no_mem
- croak_popstack
- current_re_engine
- custom_op_get_field
- cv_ckproto_len_flags
- cv_clone_into
- cv_const_sv_or_av
- cv_undef_flags
- cvgv_from_hek
- cvgv_set
- cvstash_set
- deb_stack_all
- defelem_target
- delete_eval_scope
- die_unwind
- do_aexec
- do_aexec5
- do_eof
- do_exec
- do_exec3
- do_execfree
- do_ipcctl
- do_ipcget
- do_msgrcv
- do_msgsnd
- do_ncmp
- do_open6
- do_open_raw
- do_print
- do_readline
- do_seek
- do_semop
- do_shmio
- do_sysseek
- do_tell
- do_trans
- do_vecget
- do_vecset
- do_vop
- dofile
- drand48_init_r
- drand48_r
- dump_all_perl
- dump_packsubs_perl
- dump_sub_perl
- dump_sv_child
- emulate_cop_io
- feature_is_enabled
- find_lexical_cv
- find_runcv_where
- find_rundefsv2
- find_script
- free_tied_hv_pool
- get_and_check_backslash_N_name
- get_db_sub
- get_debug_opts
- get_hash_seed
- get_invlist_iter_addr
- get_invlist_offset_addr
- get_invlist_previous_index_addr
- get_no_modify
- get_opargs
- get_re_arg
- getenv_len
- grok_atoUV
- grok_bslash_x
- gv_fetchmeth_internal
- gv_override
- gv_setref
- gv_stashpvn_internal
- gv_stashsvpvn_cached
- hfree_next_entry
- hv_backreferences_p
- hv_kill_backrefs
- hv_placeholders_p
- hv_undef_flags
- init_argv_symbols
- init_constants
- init_dbargs
- init_debugger
- invert
- invlist_array
- invlist_clone
- invlist_highest
- invlist_is_iterating
- invlist_iterfinish
- invlist_iterinit
- invlist_max
- invlist_previous_index
- invlist_set_len
- invlist_set_previous_index
- invlist_trim
- io_close
- is_utf8_common
- isinfnansv
- jmaybe
- keyword
- keyword_plugin_standard
- list
- localize
- magic_clear_all_env
- magic_cleararylen_p
- magic_clearenv
- magic_clearisa
- magic_clearpack
- magic_clearsig
- magic_copycallchecker
- magic_existspack
- magic_freearylen_p
- magic_freeovrld
- magic_get
- magic_getarylen
- magic_getdebugvar
- magic_getdefelem
- magic_getnkeys
- magic_getpack
- magic_getpos
- magic_getsig
- magic_getsubstr
- magic_gettaint
- magic_getuvar
- magic_getvec
- magic_killbackrefs
- magic_nextpack
- magic_regdata_cnt
- magic_regdatum_get
- magic_regdatum_set
- magic_scalarpack
- magic_set
- magic_set_all_env
- magic_setarylen
- magic_setcollxfrm
- magic_setdbline
- magic_setdebugvar
- magic_setdefelem
- magic_setenv
- magic_setisa
- magic_setlvref
- magic_setmglob
- magic_setnkeys
- magic_setpack
- magic_setpos
- magic_setregexp
- magic_setsig
- magic_setsubstr
- magic_settaint
- magic_setutf8
- magic_setuvar
- magic_setvec
- magic_sizepack
- magic_wipepack
- malloc_good_size
- malloced_size
- mem_collxfrm
- mem_log_alloc
- mem_log_free
- mem_log_realloc
- mg_find_mglob
- mode_from_discipline
- more_bodies
- mro_meta_dup
- mro_meta_init
- multideref_stringify
- my_attrs
- my_clearenv
- my_lstat_flags
- my_stat_flags
- my_unexec
- newATTRSUB_x
- newGP
- newMETHOP_internal
- newSTUB
- newSVavdefelem
- newXS_deffile
- newXS_len_flags
- new_warnings_bitfield
- nextargv
- noperl_die
- oopsAV
- oopsHV
- op_clear
- op_integerize
- op_lvalue_flags
- op_refcnt_dec
- op_refcnt_inc
- op_relocate_sv
- op_std_init
- op_unscope
- opmethod_stash
- opslab_force_free
- opslab_free
- opslab_free_nopad
- package
- package_version
- pad_add_weakref
- padlist_store
- padname_free
- padnamelist_free
- parse_subsignature
- parse_unicode_opts
- parser_free
- parser_free_nexttoke_ops
- path_is_searchable
- peep
- pmruntime
- populate_isa
- ptr_hash
- qerror
- re_op_compile
- reg_named_buff
- reg_named_buff_iter
- reg_numbered_buff_fetch
- reg_numbered_buff_length
- reg_numbered_buff_store
- reg_qr_package
- reg_skipcomment
- reg_temp_copy
- regcurly
- regpposixcc
- regprop
- report_evil_fh
- report_redefined_cv
- report_wrongway_fh
- rpeep
- rsignal_restore
- rsignal_save
- rxres_save
- same_dirent
- save_aliased_sv
- save_strlen
- sawparens
- scalar
- scalarvoid
- set_caret_X
- set_padlist
- should_warn_nl
- sighandler
- softref2xv
- ssc_add_range
- ssc_clear_locale
- ssc_cp_and
- ssc_intersection
- ssc_union
- sub_crush_depth
- sv_add_backref
- sv_buf_to_ro
- sv_del_backref
- sv_free2
- sv_kill_backrefs
- sv_len_utf8_nomg
- sv_magicext_mglob
- sv_mortalcopy_flags
- sv_only_taint_gmagic
- sv_or_pv_pos_u2b
- sv_resetpvn
- sv_sethek
- sv_setsv_cow
- sv_unglob
- tied_method
- tmps_grow_p
- translate_substr_offsets
- try_amagic_bin
- try_amagic_un
- unshare_hek
- utilize
- varname
- vivify_defelem
- vivify_ref
- wait4pid
- was_lvalue_sub
- watch
- win32_croak_not_implemented
- write_to_stderr
- xs_boot_epilog
- xs_handshake
- yyerror
- yyerror_pv
- yyerror_pvn
- yylex
- yyparse
- yyunlex