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在阅读PHP源码的时候,会遇到很多诸如:CG(),EG() ,PG(),FG()这样的宏,如果不了解这些宏的意义,会给理解源码造成很大困难
EG()、这个宏可以用来访问符号表,函数,资源信息和常量
CG() 用来访问核心全局变量
PG() PHP全局变量。我们知道php.ini会映射一个或者多个PHP全局结构。举几个使用这个宏的例子:PG(register_globals), PG(safe_mode), PG(memory_limit)
FG() 文件全局变量。大多数文件I/O或相关的全局变量的数据流都塞进标准扩展出口结构。
申明 Zend/zend_globals_macros.h
typedef struct _zend_compiler_globals zend_compiler_globals; typedef struct _zend_executor_globals zend_executor_globals; /* Compiler */ #ifdef ZTS # define CG(v) TSRMG(compiler_globals_id, zend_compiler_globals *, v) int zendparse(void *compiler_globals); #else # define CG(v) (compiler_globals.v) extern ZEND_API struct _zend_compiler_globals compiler_globals; int zendparse(void); #endif /* Executor */ #ifdef ZTS # define EG(v) TSRMG(executor_globals_id, zend_executor_globals *, v) #else # define EG(v) (executor_globals.v) extern ZEND_API zend_executor_globals executor_globals; #endif
结构体中的具体定义 Zend/zend_globals.h
/* Define ZTS if you want a thread-safe Zend */ /*#undef ZTS*/ #ifdef ZTS BEGIN_EXTERN_C() ZEND_API extern int compiler_globals_id; ZEND_API extern int executor_globals_id; END_EXTERN_C() #endif
struct _zend_compiler_globals
struct _zend_compiler_globals { zend_stack bp_stack; zend_stack switch_cond_stack; zend_stack foreach_copy_stack; zend_stack object_stack; zend_stack declare_stack; zend_class_entry *active_class_entry; /* variables for list() compilation */ zend_llist list_llist; zend_llist dimension_llist; zend_stack list_stack; zend_stack function_call_stack; char *compiled_filename; int zend_lineno; zend_op_array *active_op_array; HashTable *function_table; /* function symbol table */ HashTable *class_table; /* class table */ HashTable filenames_table; HashTable *auto_globals; zend_bool parse_error; zend_bool in_compilation; zend_bool short_tags; zend_bool asp_tags; zend_declarables declarables; zend_bool unclean_shutdown; zend_bool ini_parser_unbuffered_errors; zend_llist open_files; long catch_begin; struct _zend_ini_parser_param *ini_parser_param; int interactive; zend_uint start_lineno; zend_bool increment_lineno; znode implementing_class; zend_uint access_type; char *doc_comment; zend_uint doc_comment_len; zend_uint compiler_options; /* set of ZEND_COMPILE_* constants */ zval *current_namespace; HashTable *current_import; HashTable *current_import_function; HashTable *current_import_const; zend_bool in_namespace; zend_bool has_bracketed_namespaces; HashTable const_filenames; zend_compiler_context context; zend_stack context_stack; /* interned strings */ char *interned_strings_start; char *interned_strings_end; char *interned_strings_top; char *interned_strings_snapshot_top; #ifndef ZTS char *interned_empty_string; #endif HashTable interned_strings; const zend_encoding **script_encoding_list; size_t script_encoding_list_size; zend_bool multibyte; zend_bool detect_unicode; zend_bool encoding_declared; #ifdef ZTS zval ***static_members_table; int last_static_member; #endif };
struct _zend_executor_globals
struct _zend_executor_globals { zval **return_value_ptr_ptr; zval uninitialized_zval; zval *uninitialized_zval_ptr; zval error_zval; zval *error_zval_ptr; /* symbol table cache */ HashTable *symtable_cache[SYMTABLE_CACHE_SIZE]; HashTable **symtable_cache_limit; HashTable **symtable_cache_ptr; zend_op **opline_ptr; HashTable *active_symbol_table; HashTable symbol_table; /* main symbol table */ HashTable included_files; /* files already included */ JMP_BUF *bailout; int error_reporting; int orig_error_reporting; int exit_status; zend_op_array *active_op_array; HashTable *function_table; /* function symbol table */ HashTable *class_table; /* class table */ HashTable *zend_constants; /* constants table */ zend_class_entry *scope; zend_class_entry *called_scope; /* Scope of the calling class */ zval *This; long precision; int ticks_count; zend_bool in_execution; HashTable *in_autoload; zend_function *autoload_func; zend_bool full_tables_cleanup; /* for extended information support */ zend_bool no_extensions; #ifdef ZEND_WIN32 zend_bool timed_out; OSVERSIONINFOEX windows_version_info; #endif HashTable regular_list; HashTable persistent_list; zend_vm_stack argument_stack; int user_error_handler_error_reporting; zval *user_error_handler; zval *user_exception_handler; zend_stack user_error_handlers_error_reporting; zend_ptr_stack user_error_handlers; zend_ptr_stack user_exception_handlers; zend_error_handling_t error_handling; zend_class_entry *exception_class; /* timeout support */ int timeout_seconds; int lambda_count; HashTable *ini_directives; HashTable *modified_ini_directives; zend_ini_entry *error_reporting_ini_entry; zend_objects_store objects_store; zval *exception, *prev_exception; zend_op *opline_before_exception; zend_op exception_op[3]; struct _zend_execute_data *current_execute_data; struct _zend_module_entry *current_module; zend_property_info std_property_info; zend_bool active; zend_op *start_op; void *saved_fpu_cw_ptr; #if XPFPA_HAVE_CW XPFPA_CW_DATATYPE saved_fpu_cw; #endif void *reserved[ZEND_MAX_RESERVED_RESOURCES]; };
一般EG用的比较多
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原文地址:http://www.cnblogs.com/chenpingzhao/p/4822771.html