Provided by: manpages-zh_1.5.2-1.1_all bug

NAME

       ckalloc,   memory,  ckfree,  Tcl_DisplayMemory,  Tcl_InitMemory,  Tcl_ValidateAllMemory  -
       合法的内存分配接口

总览 SYNOPSIS

       memory info

       memory trace [on|off]

       memory validate [on|off]

       memory trace_on_at_malloc nnn

       memory break_on_malloc nnn

       memory display file

       #include <tcl.h>

       char *
       ckalloc (unsigned size)

       void
       ckfree (char *ptr)

       int
       Tcl_DumpActiveMemory (char *fileName);

       void
       Tcl_ValidateAllMemory (char *file,
                              int   line)

       void
       Tcl_InitMemory (interp)

ARGUMENTS

       Tcl_Interp *fileName uint size in

       char *ptr in Tcl_Interp *interp in A pointer to the Tcl interpreter.  char  *file  in  The
       filename  of  the  caller  of  Tcl_ValidateAllMemory.   int line in The line number of the
       caller of Tcl_ValidateAllMemory.  char *fileName in File to display list of active memory.

描述 DESCRIPTION

   ckalloc
       This macro allocates memory, in the same manner as malloc, with the following differences:
       One, ckalloc checks the value returned from malloc (it calls malloc for you) and panics if
       the allocation request fails.  Two, if enabled at compile time, a version of ckalloc  with
       special  memory  debugging capabilities replaces the normal version of ckalloc, which aids
       in  detecting  memory  overwrites  and  leaks  (repeated  allocations   not   matched   by
       corresponding frees).

       Parameters:
         o size - The size of the memory block to be allocated.

       Returns:
         A pointer to the allocated memory block.

   ckfree
       This  macro  frees  memory  allocated  by ckalloc.  Like ckalloc, when memory debugging is
       enabled, ckfree has enhanced capabilities for detecting memory overwrites and leaks.

       It is very important that you use ckalloc when you need to allocate memory, and  that  you
       use  ckfree  to  free  it.  Should you use malloc to allocate and ckfree to free, spurious
       memory validation errors will occur when memory debugging is enabled.  Should you use free
       to free memory allocated by ckalloc, memory corruption will occur when memory debugging is
       enabled.  Any memory that is to be become the property of the  Tcl  interpreter,  such  as
       result  space,  must  be  allocated  with  ckalloc.   If it is absolutely necessary for an
       application to pass back malloced memory to Tcl, it will work only if Tcl is complied with
       the  TCL_MEM_DEBUG flag turned off.  If you convert your application to use this facility,
       it will help you find memory over runs and lost memory.  Note that memory allocated by a C
       library  routine  requiring freeing should still be freed with free, since it calls malloc
       rather than ckalloc to do the allocation.

       Parmeters:
         o ptr - The address of a block to free, as returned by ckalloc.

   Tcl_DumpActiveMemory
       This function will output a list of all currently allocated memory to the specified  file.
       The  following  information  is outputted for each allocated block of memory: starting and
       ending addresses (excluding guard zone), size, source file where  ckalloc  was  called  to
       allocate  the  block  and  line  number  in  that  file.   It is especially useful to call
       Tcl_DumpActiveMemory after the Tcl interpreter has been deleted.

       Parameters:
         o fileName - The name of the file to output the memory list to.

   Tcl_ValidateAllMemory
       Forces a validation of the guard zones  of  all  currently  allocated  blocks  of  memory.
       Normally  validation  of a block occurs when its freed, unless full validation is enabled,
       in which case validation of all blocks occurs when ckalloc and ckfree  are  called.   This
       function forces the validation to occur at any point.

       Parameters:
         o file - The file that this routine is being called from, normally __FILE__.
         o line - The line that this routine is being called from, normally __LINE__.

ENABLING MEMORY DEBUGGING

       To  enable  memory  debugging,  Tcl  should  be recompiled from scratch with TCL_MEM_DEBUG
       defined.  This will also compile in a non-stub version of Tcl_InitMemory to add the memory
       command to Tcl.

       TCL_MEM_DEBUG  must  be  either  left defined for all modules or undefined for all modules
       that are going to be linked together.  If they are  not,  link  errors  will  occur,  with
       either TclDbCkfree and Tcl_DbCkalloc or Tcl_Ckalloc and Tcl_Ckfree being undefined.

GUARD ZONES

       When memory debugging is enabled, whenever a call to ckalloc is made, slightly more memory
       than requested is allocated so the memory debugging code can keep track of  the  allocated
       memory,  and  also  eight-byte ``guard zones'' are placed in front of and behind the space
       that will be returned to the caller.  (The size of the guard zone  is  defined  by  the  C
       #define  GUARD_SIZE  in  baseline/src/ckalloc.c -- it can be extended if you suspect large
       overwrite problems, at some cost in performance.)  A known pattern  is  written  into  the
       guard zones and, on a call to ckfree, the guard zones of the space being freed are checked
       to see if either zone has been modified in any way.  If one has been, the guard bytes  and
       their  new  contents  are  identified, and a ``low guard failed'' or ``high guard failed''
       message is issued.  The ``guard failed'' message includes the address of the memory packet
       and  the  file  name  and  line number of the code that called ckfree.  This allows you to
       detect the common sorts of one-off problems, where  not  enough  space  was  allocated  to
       contain the data written, for example.

THE MEMORY COMMAND

       memory options
              The  Tcl  memory  command gives the Tcl developer control of Tcl's memory debugging
              capabilities.  The memory command  has  several  suboptions,  which  are  described
              below.   It  is  only  available  when  Tcl has been compiled with memory debugging
              enabled.

       memory info
              生成一个报告,包含自从                                                          Tcl
              启动以来分配和释放的(内存)总数,当前分配的包(未遇到相应的到    ckfree    的调用的到
              ckalloc
              的调用的当前数目)的数目,当前分配的字节数,和已分配的包和字节的最大的数目。

       memory trace [on|off]
              使内存跟踪开启或关闭。在开启内存跟踪的时候,对     ckalloc       的每次调用都导致向
              stderr                                                   写一行跟踪信息,其组成有字
              ckalloc,随后是返回的地址,分配的内存总数,和进行分配的                           C
              文件名和代码的行数。例如:...

                 ckalloc 40e478 98 tclProc.c 1406

              Calls to ckfree are traced in the same manner, except  that  the  word  ckalloc  is
              replaced by the word ckfree.

       memory validate [on|off]
              使内存生效(validation)开启或关闭。在开启内存生效的时候,在对ckallocckfree
              的每次调用上,检查用           ckalloc           分配的每块现存的内存的守卫区(guard
              zone)。这有很大的性能影响而只在强烈怀疑有覆写(overwrite)问题的时候才使用。开启内存生效的益处是在覆写发生之后第一次调用
              ckallocckfree
              的时候就能检测到守卫区覆写,而不是在释放有覆写守卫区的内存的时候,释放可能在内存覆写发生之后才发生。

       memory trace_on_at_malloc nnn
              在进行了   count   数目   ckalloc    之后启用内存跟踪。例如,如果你键入了    memory
              trace_on_at_malloc          100,在第            100         次调用         ckalloc
              之后,将对所有分配和释放的内存显示内存跟踪信息。因为在一个问题发生之前可能有许多内存活动,如果你能在问题出现(
              sets
              in)之前标识出一定数目的分配,决定(judicious)使用这个选项可以减轻跟踪导致的速度变慢(和生成的跟踪信息总数)。在发生一个守卫区错误时,输出自从
              Tcl  启动以来发生的内存分配的当前数目。

       memory break_on_malloc nnn
              在进行了  count   数目的  ckalloc  分配之后,输出一个(中断)消息,表示它现在想进入 C
              调试器。   Tcl   将向自身发出一个  SIGINT    信号。如果你在一个   C    调试器下运行
              Tcl,它将接着进入调试器命令模式。

       memory display file
              向指定文件写当前所有分配的内存的一个列表。

DEBUGGING DIFFICULT MEMORY CORRUPTION PROBLEMS

       Normally,  Tcl  compiled  with  memory  debugging  enabled  will make it easy to isolate a
       corruption problem.  Turning on memory validation with the memory command can help isolate
       difficult  problems.  If you suspect (or know) that corruption is occurring before the Tcl
       interpreter comes up far enough for you  to  issue  commands,  you  can  set  MEM_VALIDATE
       define,  recompile  tclCkalloc.c and rebuild Tcl.  This will enable memory validation from
       the first call to ckalloc, again, at a large performance impact.

       If you are desperate and validating memory on every  call  to  ckalloc  and  ckfree  isn't
       enough,  you  can explicitly call Tcl_ValidateAllMemory directly at any point.  It takes a
       char * and an int which are normally the filename and line number of the caller, but  they
       can  actually  be  anything  you  want.   Remember  to remove the calls after you find the
       problem.

关键字 KEYWORDS

       ckalloc, ckfree, free, memory, malloc

[中文版维护人]

       寒蝉退士

[中文版最新更新]

       2001/09/28

《中国 Linux 论坛 man 手册页翻译计划》:

       http://cmpp.linuxforum.net