请教malloc：Error accessing memory address 0x0: 无效的变元

Cion

1. 
   
2. string timestr("");//时间文字
   
3. if(time_flag==1)
   
4. {
   
5.   struct tm *now;
   
6.   char str_t[40];
   
7.   now   = localtime(&timer);  
   
8.   sprintf(str_t,"%02d:%02d:%02d:",now->tm_hour,now->tm_min,now->tm_sec);
   
9.   timestr=str_t;    // 此处core dump
   
10. ……

复制代码

gdb -c core
Detected 64-bit corefile.
Invoking /opt/langtools/bin/gdb64.
HP gdb 3.3 for PA-RISC 2.0 (wide), HP-UX 11.00.
Copyright 1986 - 2001 Free Software Foundation, Inc.
Hewlett-Packard Wildebeest 3.3 (based on GDB) is covered by the
GNU General Public License. Type "show copying" to see the conditions to
change it and/or distribute copies. Type "show warranty" for warranty/support.

Reading symbols from CallComparator...done.
Core was generated by `CallComparator'.
Program terminated with signal 11, Segmentation fault.

warning: The shared libraries were not privately mapped; setting a
breakpoint in a shared library will not work until you rerun the program.

wher
warning: section .data not found in /arrayindb/app/oracle/app/oracle9/product/9.2.0/lib/libwtc9.sl
e#0  0x800003ffbef82558 in .stub+0x460 () from /usr/lib/pa20_64//libc.2
(gdb) where
#0  0x800003ffbef82558 in .stub+0x460 () from /usr/lib/pa20_64//libc.2
#1  0x800003ffbef7fef8 in .stub+0x680 () from /usr/lib/pa20_64//libc.2
#2  0x800003ffbef8566c in malloc+0x1c4 () from /usr/lib/pa20_64//libc.2
Error accessing memory address 0x0: 无效的变元.
(gdb)

cugb_cat

timestr是常量？
string类型和char []类型是一回事吗？

Cion

又出错了，详细信息是：
(gdb)
0x800003ffbefe418c in time+0x2c () from /usr/lib/pa20_64//libc.2
(gdb)
Single stepping until exit from function time,
which has no line number information.
CLogManager::WriteLog (this=0x800000010004bfd0, str={<class std::allocator<char>> = {<No data fields>},
      static npos = 18446744073709551615, static __nullref = {__ref_hdr_ = {__mutex_ = {<struct __rw::__rw_mutex_base> = {
              _C_mutex = {<No data fields>}}, <No data fields>}, __refs_ = 1, __capacity_ = 0, __nchars_ = 0},
        __eos_char_ = 0 '\000'}, _C_data = 0x8000000100295578 "正在遍历本方（主叫）数据源... (遍历数10001/总数3761033)"},
    warnlevel=0, time_flag=1, throwex=true) at ../public/LogManager.cpp:153
153                     now   = localtime(&timer);      
(gdb) p now
$19 = (struct tm *) 0x800003ffbfff1d70
(gdb) p *now
$20 = {tm_sec = 0, tm_min = 0, tm_hour = -2147482625, tm_mday = -1089454912, tm_mon = -2147482625, tm_year = -1091123745,
  tm_wday = 0, tm_yday = 310536, tm_isdst = -1}
(gdb) n
154                     sprintf(str_t,"%02d:%02d:%02d:",now->tm_hour,now->tm_min,now->tm_sec);
(gdb) p *now
$21 = {tm_sec = 59, tm_min = 46, tm_hour = 17, tm_mday = 16, tm_mon = 9, tm_year = 107, tm_wday = 2, tm_yday = 288, tm_isdst = 0}
(gdb) n
155                     timestr=str_t;
(gdb) p str_t
$22 = "17:46:59:\000\000\001\000\004絓b

augustusqing

timestr=str_t;    // 此处core dump

试试：

timestr.assign(str_t)

Alligator27

我的经验，在此之前已经有memory corruption. 建议用debug allocator 试试

Cion

原帖由 Alligator27 于 2007-10-16 21:05 发表
我的经验，在此之前已经有memory corruption. 建议用debug allocator 试试

是。我的经验也是，应该错误在此之前。
但是我跟踪了多次，都在此处core dump。

请教debug allocator是什么操作？

Alligator27

我的意思是诊断memory error的工具，HP gdb有这功能。

xB1ue

有点怪，暂时不知道原因，看你调试的结果了。

另外，localtime 是非线程安全的，如果你是在多线程环境下跑，试试换成 localtime_r 再看看呢？