# 打印程序動態分配內存的信息 ## 例子 #include <stdio.h> #include <malloc.h> int main(void) { char *p[10]; int i = 0; for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) { p[i] = malloc(100000); } return 0; } ## 技巧 用gdb調試程序時，可以用下面的自定義命令，打印程序動態分配內存的信息： define mallocinfo set $__f = fopen("/dev/tty", "w") call malloc_info(0, $__f) call fclose($__f) end 以上面程序為例： Temporary breakpoint 5, main () at a.c:7 7 int i = 0; (gdb) mallocinfo <malloc version="1"> <heap nr="0"> <sizes> </sizes> <total type="fast" count="0" size="0"/> <total type="rest" count="0" size="0"/> <system type="current" size="135168"/> <system type="max" size="135168"/> <aspace type="total" size="135168"/> <aspace type="mprotect" size="135168"/> </heap> <total type="fast" count="0" size="0"/> <total type="rest" count="0" size="0"/> <system type="current" size="135168"/> <system type="max" size="135168"/> <aspace type="total" size="135168"/> <aspace type="mprotect" size="135168"/> </malloc> $20 = 0 $21 = 0 (gdb) n 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) mallocinfo <malloc version="1"> <heap nr="0"> <sizes> </sizes> <total type="fast" count="0" size="0"/> <total type="rest" count="0" size="0"/> <system type="current" size="532480"/> <system type="max" size="532480"/> <aspace type="total" size="532480"/> <aspace type="mprotect" size="532480"/> </heap> <total type="fast" count="0" size="0"/> <total type="rest" count="0" size="0"/> <system type="current" size="532480"/> <system type="max" size="532480"/> <aspace type="total" size="532480"/> <aspace type="mprotect" size="532480"/> </malloc> $22 = 0 $23 = 0 (gdb) n 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) 11 p[i] = malloc(100000); (gdb) 9 for (i = 0; i < sizeof(p)/sizeof(p[0]); i++) (gdb) mallocinfo <malloc version="1"> <heap nr="0"> <sizes> </sizes> <total type="fast" count="0" size="0"/> <total type="rest" count="0" size="0"/> <system type="current" size="1134592"/> <system type="max" size="1134592"/> <aspace type="total" size="1134592"/> <aspace type="mprotect" size="1134592"/> </heap> <total type="fast" count="0" size="0"/> <total type="rest" count="0" size="0"/> <system type="current" size="1134592"/> <system type="max" size="1134592"/> <aspace type="total" size="1134592"/> <aspace type="mprotect" size="1134592"/> </malloc> $24 = 0 $25 = 0 可以看到gdb輸出了動態分配內存的變化信息。 參見[stackoverflow](http://stackoverflow.com/questions/1471226/most-tricky-useful-commands-for-gdb-debugger). ## 貢獻者 nanxiao