我正在试验指南支持库。
此代码工作正常,Valgrind没有显示内存问题
#include <gsl>
#include <iostream>
int main() {
const int length = 10;
int *arr = new int [length];
auto _ = gsl::finally([arr] { delete[] arr; });
for (int i = 0; i<length; i++){
arr[i] = i;
}
for (int i = 0; i<length; i++){
std::cout << arr[i] << " ";
}
}
如果转让
finally
对账单
auto _
被删除,valgrind显示以下无效读/写。为什么我需要将finally语句赋给一个值,而这个值后来不再需要了?
我使用GSL Lite,版本0.28.0。
损坏的代码:
#include <gsl>
#include <iostream>
int main() {
const int length = 10;
int *arr = new int [length];
gsl::finally([arr] { delete[] arr; });
for (int i = 0; i<length; i++){
arr[i] = i;
}
for (int i = 0; i<length; i++){
std::cout << arr[i] << " ";
}
}
Valgrind输出:
==15802== Memcheck, a memory error detector
==15802== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==15802== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==15802== Command: ./a.out
==15802==
==15802== Invalid write of size 8
==15802== at 0x400E1A: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Address 0x4c3e040 is 0 bytes inside a block of size 40 free'd
==15802== at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802== by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Block was alloc'd at
==15802== at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802== by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid write of size 8
==15802== at 0x400E24: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Address 0x4c3e050 is 16 bytes inside a block of size 40 free'd
==15802== at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802== by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Block was alloc'd at
==15802== at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802== by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid write of size 4
==15802== at 0x400E2B: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Address 0x4c3e060 is 32 bytes inside a block of size 40 free'd
==15802== at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802== by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Block was alloc'd at
==15802== at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802== by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid write of size 4
==15802== at 0x400E34: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Address 0x4c3e064 is 36 bytes inside a block of size 40 free'd
==15802== at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802== by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Block was alloc'd at
==15802== at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802== by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
==15802== Invalid read of size 4
==15802== at 0x400E45: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Address 0x4c3e040 is 0 bytes inside a block of size 40 free'd
==15802== at 0x4A0862D: operator delete[](void*) (vg_replace_malloc.c:621)
==15802== by 0x400E04: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802== Block was alloc'd at
==15802== at 0x4A07898: operator new[](unsigned long) (vg_replace_malloc.c:423)
==15802== by 0x400DF4: main (in /data/home/gwe/projekte/clean_code/gsl/a.out)
==15802==
0 1 2 3 4 5 6 7 8 9 ==15802==
==15802== HEAP SUMMARY:
==15802== in use at exit: 0 bytes in 0 blocks
==15802== total heap usage: 1 allocs, 1 frees, 40 bytes allocated
==15802==
==15802== All heap blocks were freed -- no leaks are possible
==15802==
==15802== For counts of detected and suppressed errors, rerun with: -v
==15802== ERROR SUMMARY: 16 errors from 5 contexts (suppressed: 4 from 4)
