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我有存储器碎片的问题可以以这种小例子来概括:这是内存碎片吗? (视觉工作室和MinGW)
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char* argv[])
{
void *p[8000];int i,j;
p[0]=malloc(0x7F000);
if (p[0]==NULL)
printf("Alloc after failed!\n");
else
free(p[0]);
for (i=0;i<8000; i++) {
p[i]=malloc(0x40000);
if (p[i]==NULL){
printf("alloc failed for i=%d\n",i);
break;
}
}
for(j=0;j<i;j++) {
free(p[j]);
}
/*Alloc 1 will fail, Alloc 2 *might* fail, AlloC3 succeeds*/
p[0]=malloc(0x7F000);
if (p[0]==NULL)
printf("Alloc1 after failed!\n");
else {printf("alloc1 success\n");free(p[0]);}
p[0]=malloc(0x40000);
if (p[0]==NULL)
printf("Alloc2 after failed!\n");
else {printf("alloc2 success\n");free(p[0]);}
p[0]=malloc(0x10000);
if (p[0]==NULL)
printf("Alloc3 after failed!\n");
else {printf("alloc3 success\n");free(p[0]);}
printf("end");
}
该程序打印(Win7上编译MSVC(都与调试和releas分配器)和MinGW ):
alloc failed for i=7896
Alloc1 after failed!
alloc2 success
alloc3 success
end
是否有反正我可以避免这种情况?在我真正的应用程序中,我无法避免这种情况,我的程序达到了2GB的内存限制......但我希望能够通过释放某些东西来继续。
为什么碎片在这个小例子中首先发生?当我开始执行“free-s”时,为什么内存块没有压缩,因为它们应该是相邻的。
谢谢!