X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gdb%2Fgdbthread.h;h=af2dc860d1a405902b569bf042c60620b4d69eb8;hb=e56534680d0df0e2ca313086b1758480c9374615;hp=389b2fc24fcb6f886c0688320b62ea746d0a5774;hpb=8ea051c51f64f1f720b12a7424c56ac31ff9a58b;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h index 389b2fc24f..af2dc860d1 100644 --- a/gdb/gdbthread.h +++ b/gdb/gdbthread.h @@ -1,6 +1,5 @@ /* Multi-process/thread control defs for GDB, the GNU debugger. - Copyright (C) 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1997, 1998, 1999, - 2000, 2007, 2008 Free Software Foundation, Inc. + Copyright (C) 1987-2016 Free Software Foundation, Inc. Contributed by Lynx Real-Time Systems, Inc. Los Gatos, CA. @@ -22,17 +21,161 @@ #ifndef GDBTHREAD_H #define GDBTHREAD_H -struct breakpoint; -struct frame_id; struct symtab; -/* For bpstat */ #include "breakpoint.h" - -/* For struct frame_id. */ #include "frame.h" - #include "ui-out.h" +#include "inferior.h" +#include "btrace.h" +#include "common/vec.h" +#include "target/waitstatus.h" +#include "cli/cli-utils.h" + +/* Frontend view of the thread state. Possible extensions: stepping, + finishing, until(ling),... */ +enum thread_state +{ + THREAD_STOPPED, + THREAD_RUNNING, + THREAD_EXITED, +}; + +/* Inferior thread specific part of `struct infcall_control_state'. + + Inferior process counterpart is `struct inferior_control_state'. */ + +struct thread_control_state +{ + /* User/external stepping state. */ + + /* Step-resume or longjmp-resume breakpoint. */ + struct breakpoint *step_resume_breakpoint; + + /* Exception-resume breakpoint. */ + struct breakpoint *exception_resume_breakpoint; + + /* Breakpoints used for software single stepping. Plural, because + it may have multiple locations. E.g., if stepping over a + conditional branch instruction we can't decode the condition for, + we'll need to put a breakpoint at the branch destination, and + another at the instruction after the branch. */ + struct breakpoint *single_step_breakpoints; + + /* Range to single step within. + + If this is nonzero, respond to a single-step signal by continuing + to step if the pc is in this range. + + If step_range_start and step_range_end are both 1, it means to + step for a single instruction (FIXME: it might clean up + wait_for_inferior in a minor way if this were changed to the + address of the instruction and that address plus one. But maybe + not). */ + CORE_ADDR step_range_start; /* Inclusive */ + CORE_ADDR step_range_end; /* Exclusive */ + + /* Function the thread was in as of last it started stepping. */ + struct symbol *step_start_function; + + /* If GDB issues a target step request, and this is nonzero, the + target should single-step this thread once, and then continue + single-stepping it without GDB core involvement as long as the + thread stops in the step range above. If this is zero, the + target should ignore the step range, and only issue one single + step. */ + int may_range_step; + + /* Stack frame address as of when stepping command was issued. + This is how we know when we step into a subroutine call, and how + to set the frame for the breakpoint used to step out. */ + struct frame_id step_frame_id; + + /* Similarly, the frame ID of the underlying stack frame (skipping + any inlined frames). */ + struct frame_id step_stack_frame_id; + + /* Nonzero if we are presently stepping over a breakpoint. + + If we hit a breakpoint or watchpoint, and then continue, we need + to single step the current thread with breakpoints disabled, to + avoid hitting the same breakpoint or watchpoint again. And we + should step just a single thread and keep other threads stopped, + so that other threads don't miss breakpoints while they are + removed. + + So, this variable simultaneously means that we need to single + step the current thread, keep other threads stopped, and that + breakpoints should be removed while we step. + + This variable is set either: + - in proceed, when we resume inferior on user's explicit request + - in keep_going, if handle_inferior_event decides we need to + step over breakpoint. + + The variable is cleared in normal_stop. The proceed calls + wait_for_inferior, which calls handle_inferior_event in a loop, + and until wait_for_inferior exits, this variable is changed only + by keep_going. */ + int trap_expected; + + /* Nonzero if the thread is being proceeded for a "finish" command + or a similar situation when return value should be printed. */ + int proceed_to_finish; + + /* Nonzero if the thread is being proceeded for an inferior function + call. */ + int in_infcall; + + enum step_over_calls_kind step_over_calls; + + /* Nonzero if stopped due to a step command. */ + int stop_step; + + /* Chain containing status of breakpoint(s) the thread stopped + at. */ + bpstat stop_bpstat; + + /* Whether the command that started the thread was a stepping + command. This is used to decide whether "set scheduler-locking + step" behaves like "on" or "off". */ + int stepping_command; +}; + +/* Inferior thread specific part of `struct infcall_suspend_state'. */ + +struct thread_suspend_state +{ + /* Last signal that the inferior received (why it stopped). When + the thread is resumed, this signal is delivered. Note: the + target should not check whether the signal is in pass state, + because the signal may have been explicitly passed with the + "signal" command, which overrides "handle nopass". If the signal + should be suppressed, the core will take care of clearing this + before the target is resumed. */ + enum gdb_signal stop_signal; + + /* The reason the thread last stopped, if we need to track it + (breakpoint, watchpoint, etc.) */ + enum target_stop_reason stop_reason; + + /* The waitstatus for this thread's last event. */ + struct target_waitstatus waitstatus; + /* If true WAITSTATUS hasn't been handled yet. */ + int waitstatus_pending_p; + + /* Record the pc of the thread the last time it stopped. (This is + not the current thread's PC as that may have changed since the + last stop, e.g., "return" command, or "p $pc = 0xf000"). This is + used in coordination with stop_reason and waitstatus_pending_p: + if the thread's PC is changed since it last stopped, a pending + breakpoint waitstatus is discarded. */ + CORE_ADDR stop_pc; +}; + +typedef struct value *value_ptr; +DEF_VEC_P (value_ptr); +typedef VEC (value_ptr) value_vec; struct thread_info { @@ -40,50 +183,165 @@ struct thread_info ptid_t ptid; /* "Actual process id"; In fact, this may be overloaded with kernel thread id, etc. */ - int num; /* Convenient handle (GDB thread id) */ + + /* Each thread has two GDB IDs. + + a) The thread ID (Id). This consists of the pair of: + + - the number of the thread's inferior and, + + - the thread's thread number in its inferior, aka, the + per-inferior thread number. This number is unique in the + inferior but not unique between inferiors. + + b) The global ID (GId). This is a a single integer unique + between all inferiors. + + E.g.: + + (gdb) info threads -gid + Id GId Target Id Frame + * 1.1 1 Thread A 0x16a09237 in foo () at foo.c:10 + 1.2 3 Thread B 0x15ebc6ed in bar () at foo.c:20 + 1.3 5 Thread C 0x15ebc6ed in bar () at foo.c:20 + 2.1 2 Thread A 0x16a09237 in foo () at foo.c:10 + 2.2 4 Thread B 0x15ebc6ed in bar () at foo.c:20 + 2.3 6 Thread C 0x15ebc6ed in bar () at foo.c:20 + + Above, both inferiors 1 and 2 have threads numbered 1-3, but each + thread has its own unique global ID. */ + + /* The thread's global GDB thread number. This is exposed to MI, + Python/Scheme, visible with "info threads -gid", and is also what + the $_gthread convenience variable is bound to. */ + int global_num; + + /* The per-inferior thread number. This is unique in the inferior + the thread belongs to, but not unique between inferiors. This is + what the $_thread convenience variable is bound to. */ + int per_inf_num; + + /* The inferior this thread belongs to. */ + struct inferior *inf; + + /* The name of the thread, as specified by the user. This is NULL + if the thread does not have a user-given name. */ + char *name; /* Non-zero means the thread is executing. Note: this is different from saying that there is an active target and we are stopped at a breakpoint, for instance. This is a real indicator whether the thread is off and running. */ - /* This field is internal to thread.c. Never access it directly, - use is_executing instead. */ - int executing_; - - /* Frontend view of the running state. Note that this is different - from EXECUTING. When the thread is stopped internally while - handling an internal event, like a software single-step - breakpoint, executing will be false, but running will still be - true. As a possible future extension, this could turn into - enum { stopped, stepping, finishing, until(ling), ... } */ - /* This field is internal to thread.c. Never access it directly, - use is_running instead. */ - int running_; - - /* State from wait_for_inferior */ - CORE_ADDR prev_pc; - struct breakpoint *step_resume_breakpoint; - CORE_ADDR step_range_start; - CORE_ADDR step_range_end; - struct frame_id step_frame_id; + int executing; + + /* Non-zero if this thread is resumed from infrun's perspective. + Note that a thread can be marked both as not-executing and + resumed at the same time. This happens if we try to resume a + thread that has a wait status pending. We shouldn't let the + thread really run until that wait status has been processed, but + we should not process that wait status if we didn't try to let + the thread run. */ + int resumed; + + /* Frontend view of the thread state. Note that the THREAD_RUNNING/ + THREAD_STOPPED states are different from EXECUTING. When the + thread is stopped internally while handling an internal event, + like a software single-step breakpoint, EXECUTING will be false, + but STATE will still be THREAD_RUNNING. */ + enum thread_state state; + + /* If this is > 0, then it means there's code out there that relies + on this thread being listed. Don't delete it from the lists even + if we detect it exiting. */ + int refcount; + + /* State of GDB control of inferior thread execution. + See `struct thread_control_state'. */ + struct thread_control_state control; + + /* State of inferior thread to restore after GDB is done with an inferior + call. See `struct thread_suspend_state'. */ + struct thread_suspend_state suspend; + int current_line; struct symtab *current_symtab; - int trap_expected; - int stepping_over_breakpoint; - /* This is set TRUE when a catchpoint of a shared library event - triggers. Since we don't wish to leave the inferior in the - solib hook when we report the event, we step the inferior - back to user code before stopping and reporting the event. */ - int stepping_through_solib_after_catch; + /* Internal stepping state. */ - /* When stepping_through_solib_after_catch is TRUE, this is a - list of the catchpoints that should be reported as triggering - when we finally do stop stepping. */ - bpstat stepping_through_solib_catchpoints; + /* Record the pc of the thread the last time it was resumed. (It + can't be done on stop as the PC may change since the last stop, + e.g., "return" command, or "p $pc = 0xf000"). This is maintained + by proceed and keep_going, and among other things, it's used in + adjust_pc_after_break to distinguish a hardware single-step + SIGTRAP from a breakpoint SIGTRAP. */ + CORE_ADDR prev_pc; + + /* Did we set the thread stepping a breakpoint instruction? This is + used in conjunction with PREV_PC to decide whether to adjust the + PC. */ + int stepped_breakpoint; + + /* Should we step over breakpoint next time keep_going is called? */ + int stepping_over_breakpoint; + + /* Should we step over a watchpoint next time keep_going is called? + This is needed on targets with non-continuable, non-steppable + watchpoints. */ + int stepping_over_watchpoint; + + /* Set to TRUE if we should finish single-stepping over a breakpoint + after hitting the current step-resume breakpoint. The context here + is that GDB is to do `next' or `step' while signal arrives. + When stepping over a breakpoint and signal arrives, GDB will attempt + to skip signal handler, so it inserts a step_resume_breakpoint at the + signal return address, and resume inferior. + step_after_step_resume_breakpoint is set to TRUE at this moment in + order to keep GDB in mind that there is still a breakpoint to step over + when GDB gets back SIGTRAP from step_resume_breakpoint. */ + int step_after_step_resume_breakpoint; + + /* Pointer to the state machine manager object that handles what is + left to do for the thread's execution command after the target + stops. Several execution commands use it. */ + struct thread_fsm *thread_fsm; + + /* This is used to remember when a fork or vfork event was caught by + a catchpoint, and thus the event is to be followed at the next + resume of the thread, and not immediately. */ + struct target_waitstatus pending_follow; + + /* True if this thread has been explicitly requested to stop. */ + int stop_requested; + + /* The initiating frame of a nexting operation, used for deciding + which exceptions to intercept. If it is null_frame_id no + bp_longjmp or bp_exception but longjmp has been caught just for + bp_longjmp_call_dummy. */ + struct frame_id initiating_frame; /* Private data used by the target vector implementation. */ - struct private_thread_info *private; + struct private_thread_info *priv; + + /* Function that is called to free PRIVATE. If this is NULL, then + xfree will be called on PRIVATE. */ + void (*private_dtor) (struct private_thread_info *); + + /* Branch trace information for this thread. */ + struct btrace_thread_info btrace; + + /* Flag which indicates that the stack temporaries should be stored while + evaluating expressions. */ + int stack_temporaries_enabled; + + /* Values that are stored as temporaries on stack while evaluating + expressions. */ + value_vec *stack_temporaries; + + /* Step-over chain. A thread is in the step-over queue if these are + non-NULL. If only a single thread is in the chain, then these + fields point to self. */ + struct thread_info *step_over_prev; + struct thread_info *step_over_next; }; /* Create an empty thread list, or empty the existing one. */ @@ -111,95 +369,267 @@ extern void delete_thread (ptid_t); exited, for example. */ extern void delete_thread_silent (ptid_t); -/* Delete a step_resume_breakpoint from the thread database. */ -extern void delete_step_resume_breakpoint (void *); +/* Delete a step_resume_breakpoint from the thread database. */ +extern void delete_step_resume_breakpoint (struct thread_info *); + +/* Delete an exception_resume_breakpoint from the thread database. */ +extern void delete_exception_resume_breakpoint (struct thread_info *); -/* Translate the integer thread id (GDB's homegrown id, not the system's) - into a "pid" (which may be overloaded with extra thread information). */ -extern ptid_t thread_id_to_pid (int); +/* Delete the single-step breakpoints of thread TP, if any. */ +extern void delete_single_step_breakpoints (struct thread_info *tp); -/* Translate a 'pid' (which may be overloaded with extra thread information) - into the integer thread id (GDB's homegrown id, not the system's). */ -extern int pid_to_thread_id (ptid_t ptid); +/* Check if the thread has software single stepping breakpoints + set. */ +extern int thread_has_single_step_breakpoints_set (struct thread_info *tp); + +/* Check whether the thread has software single stepping breakpoints + set at PC. */ +extern int thread_has_single_step_breakpoint_here (struct thread_info *tp, + struct address_space *aspace, + CORE_ADDR addr); + +/* Translate the global integer thread id (GDB's homegrown id, not the + system's) into a "pid" (which may be overloaded with extra thread + information). */ +extern ptid_t global_thread_id_to_ptid (int num); + +/* Translate a 'pid' (which may be overloaded with extra thread + information) into the global integer thread id (GDB's homegrown id, + not the system's). */ +extern int ptid_to_global_thread_id (ptid_t ptid); + +/* Returns whether to show inferior-qualified thread IDs, or plain + thread numbers. Inferior-qualified IDs are shown whenever we have + multiple inferiors, or the only inferior left has number > 1. */ +extern int show_inferior_qualified_tids (void); + +/* Return a string version of THR's thread ID. If there are multiple + inferiors, then this prints the inferior-qualifier form, otherwise + it only prints the thread number. The result is stored in a + circular static buffer, NUMCELLS deep. */ +const char *print_thread_id (struct thread_info *thr); /* Boolean test for an already-known pid (which may be overloaded with extra thread information). */ extern int in_thread_list (ptid_t ptid); -/* Boolean test for an already-known thread id (GDB's homegrown id, - not the system's). */ -extern int valid_thread_id (int thread); +/* Boolean test for an already-known global thread id (GDB's homegrown + global id, not the system's). */ +extern int valid_global_thread_id (int global_id); /* Search function to lookup a thread by 'pid'. */ -extern struct thread_info *find_thread_pid (ptid_t ptid); +extern struct thread_info *find_thread_ptid (ptid_t ptid); + +/* Find thread by GDB global thread ID. */ +struct thread_info *find_thread_global_id (int global_id); + +/* Finds the first thread of the inferior given by PID. If PID is -1, + returns the first thread in the list. */ +struct thread_info *first_thread_of_process (int pid); + +/* Returns any thread of process PID, giving preference to the current + thread. */ +extern struct thread_info *any_thread_of_process (int pid); + +/* Returns any non-exited thread of process PID, giving preference to + the current thread, and to not executing threads. */ +extern struct thread_info *any_live_thread_of_process (int pid); + +/* Change the ptid of thread OLD_PTID to NEW_PTID. */ +void thread_change_ptid (ptid_t old_ptid, ptid_t new_ptid); /* Iterator function to call a user-provided callback function once for each known thread. */ typedef int (*thread_callback_func) (struct thread_info *, void *); extern struct thread_info *iterate_over_threads (thread_callback_func, void *); +/* Traverse all threads. */ +#define ALL_THREADS(T) \ + for (T = thread_list; T; T = T->next) \ + +/* Traverse over all threads, sorted by inferior. */ +#define ALL_THREADS_BY_INFERIOR(inf, tp) \ + ALL_INFERIORS (inf) \ + ALL_THREADS (tp) \ + if (inf == tp->inf) + +/* Traverse all threads, except those that have THREAD_EXITED + state. */ + +#define ALL_NON_EXITED_THREADS(T) \ + for (T = thread_list; T; T = T->next) \ + if ((T)->state != THREAD_EXITED) + +/* Traverse all threads, including those that have THREAD_EXITED + state. Allows deleting the currently iterated thread. */ +#define ALL_THREADS_SAFE(T, TMP) \ + for ((T) = thread_list; \ + (T) != NULL ? ((TMP) = (T)->next, 1): 0; \ + (T) = (TMP)) + extern int thread_count (void); -/* infrun context switch: save the debugger state for the given thread. */ -extern void save_infrun_state (ptid_t ptid, - CORE_ADDR prev_pc, - int trap_expected, - struct breakpoint *step_resume_breakpoint, - CORE_ADDR step_range_start, - CORE_ADDR step_range_end, - const struct frame_id *step_frame_id, - int another_trap, - int stepping_through_solib_after_catch, - bpstat stepping_through_solib_catchpoints, - int current_line, - struct symtab *current_symtab); - -/* infrun context switch: load the debugger state previously saved - for the given thread. */ -extern void load_infrun_state (ptid_t ptid, - CORE_ADDR *prev_pc, - int *trap_expected, - struct breakpoint **step_resume_breakpoint, - CORE_ADDR *step_range_start, - CORE_ADDR *step_range_end, - struct frame_id *step_frame_id, - int *another_trap, - int *stepping_through_solib_affter_catch, - bpstat *stepping_through_solib_catchpoints, - int *current_line, - struct symtab **current_symtab); - -/* Switch from one thread to another. */ +/* Switch from one thread to another. Also sets the STOP_PC + global. */ extern void switch_to_thread (ptid_t ptid); +/* Switch from one thread to another. Does not read registers and + sets STOP_PC to -1. */ +extern void switch_to_thread_no_regs (struct thread_info *thread); + +/* Marks or clears thread(s) PTID as resumed. If PTID is + MINUS_ONE_PTID, applies to all threads. If ptid_is_pid(PTID) is + true, applies to all threads of the process pointed at by PTID. */ +extern void set_resumed (ptid_t ptid, int resumed); + /* Marks thread PTID is running, or stopped. - If PIDGET (PTID) is -1, marks all threads. */ + If PTID is minus_one_ptid, marks all threads. */ extern void set_running (ptid_t ptid, int running); -/* Reports if thread PTID is known to be running right now. */ +/* Marks or clears thread(s) PTID as having been requested to stop. + If PTID is MINUS_ONE_PTID, applies to all threads. If + ptid_is_pid(PTID) is true, applies to all threads of the process + pointed at by PTID. If STOP, then the THREAD_STOP_REQUESTED + observer is called with PTID as argument. */ +extern void set_stop_requested (ptid_t ptid, int stop); + +/* NOTE: Since the thread state is not a boolean, most times, you do + not want to check it with negation. If you really want to check if + the thread is stopped, + + use (good): + + if (is_stopped (ptid)) + + instead of (bad): + + if (!is_running (ptid)) + + The latter also returns true on exited threads, most likelly not + what you want. */ + +/* Reports if in the frontend's perpective, thread PTID is running. */ extern int is_running (ptid_t ptid); -/* Reports if any thread is known to be running right now. */ -extern int any_running (void); +/* Is this thread listed, but known to have exited? We keep it listed + (but not visible) until it's safe to delete. */ +extern int is_exited (ptid_t ptid); + +/* In the frontend's perpective, is this thread stopped? */ +extern int is_stopped (ptid_t ptid); -/* Marks thread PTID as executing, or as stopped. - If PIDGET (PTID) is -1, marks all threads. */ +/* Marks thread PTID as executing, or not. If PTID is minus_one_ptid, + marks all threads. + + Note that this is different from the running state. See the + description of state and executing fields of struct + thread_info. */ extern void set_executing (ptid_t ptid, int executing); /* Reports if thread PTID is executing. */ extern int is_executing (ptid_t ptid); +/* True if any (known or unknown) thread is or may be executing. */ +extern int threads_are_executing (void); + +/* Merge the executing property of thread PTID over to its thread + state property (frontend running/stopped view). + + "not executing" -> "stopped" + "executing" -> "running" + "exited" -> "exited" + + If PTID is minus_one_ptid, go over all threads. + + Notifications are only emitted if the thread state did change. */ +extern void finish_thread_state (ptid_t ptid); + +/* Same as FINISH_THREAD_STATE, but with an interface suitable to be + registered as a cleanup. PTID_P points to the ptid_t that is + passed to FINISH_THREAD_STATE. */ +extern void finish_thread_state_cleanup (void *ptid_p); + /* Commands with a prefix of `thread'. */ extern struct cmd_list_element *thread_cmd_list; +extern void thread_command (char *tidstr, int from_tty); + /* Print notices on thread events (attach, detach, etc.), set with `set print thread-events'. */ extern int print_thread_events; -extern void print_thread_info (struct ui_out *uiout, int thread); +/* Prints the list of threads and their details on UIOUT. If + REQUESTED_THREADS, a list of GDB ids/ranges, is not NULL, only + print threads whose ID is included in the list. If PID is not -1, + only print threads from the process PID. Otherwise, threads from + all attached PIDs are printed. If both REQUESTED_THREADS is not + NULL and PID is not -1, then the thread is printed if it belongs to + the specified process. Otherwise, an error is raised. */ +extern void print_thread_info (struct ui_out *uiout, char *requested_threads, + int pid); + +extern struct cleanup *make_cleanup_restore_current_thread (void); + +/* Returns a pointer into the thread_info corresponding to + INFERIOR_PTID. INFERIOR_PTID *must* be in the thread list. */ +extern struct thread_info* inferior_thread (void); + +extern void update_thread_list (void); + +/* Delete any thread the target says is no longer alive. */ + +extern void prune_threads (void); + +/* Delete threads marked THREAD_EXITED. Unlike prune_threads, this + does not consult the target about whether the thread is alive right + now. */ +extern void delete_exited_threads (void); + +/* Return true if PC is in the stepping range of THREAD. */ + +int pc_in_thread_step_range (CORE_ADDR pc, struct thread_info *thread); + +extern struct cleanup *enable_thread_stack_temporaries (ptid_t ptid); + +extern int thread_stack_temporaries_enabled_p (ptid_t ptid); + +extern void push_thread_stack_temporary (ptid_t ptid, struct value *v); + +extern struct value *get_last_thread_stack_temporary (ptid_t); + +extern int value_in_thread_stack_temporaries (struct value *, ptid_t); + +/* Add TP to the end of its inferior's pending step-over chain. */ + +extern void thread_step_over_chain_enqueue (struct thread_info *tp); + +/* Remove TP from its inferior's pending step-over chain. */ + +extern void thread_step_over_chain_remove (struct thread_info *tp); + +/* Return the next thread in the step-over chain starting at TP. NULL + if TP is the last entry in the chain. */ + +extern struct thread_info *thread_step_over_chain_next (struct thread_info *tp); + +/* Return true if TP is in the step-over chain. */ + +extern int thread_is_in_step_over_chain (struct thread_info *tp); + +/* Cancel any ongoing execution command. */ + +extern void thread_cancel_execution_command (struct thread_info *thr); + +/* Check whether it makes sense to access a register of the current + thread at this point. If not, throw an error (e.g., the thread is + executing). */ +extern void validate_registers_access (void); -extern struct cleanup *make_cleanup_restore_current_thread (ptid_t, - struct frame_id); +/* Returns whether to show which thread hit the breakpoint, received a + signal, etc. and ended up causing a user-visible stop. This is + true iff we ever detected multiple threads. */ +extern int show_thread_that_caused_stop (void); +extern struct thread_info *thread_list; #endif /* GDBTHREAD_H */