运行c程序时,我遇到了以下错误:
*** glibc detected *** ./a.out: double free or corruption (!prev): 0x080b8008 ***
我认为这是由于程序结束时调用了free(),但我无法确定在此之前malloc分配的内存被释放了。以下是代码:
#include <stdio.h>
#include <stdlib.h> //malloc
#include <math.h> //sine
#define TIME 255
#define HARM 32
int main (void) {
double sineRads;
double sine;
int tcount = 0;
int hcount = 0;
/* allocate some heap memory for the large array of waveform data */
double *ptr = malloc(sizeof(double *) * TIME);
if (NULL == ptr) {
printf("ERROR: couldn't allocate waveform memory!\n");
} else {
/*evaluate and add harmonic amplitudes for each time step */
for(tcount = 0; tcount <= TIME; tcount++){
for(hcount = 0; hcount <= HARM; hcount++){
sineRads = ((double)tcount / (double)TIME) * (2*M_PI); //angular frequency
sineRads *= (hcount + 1); //scale frequency by harmonic number
sine = sin(sineRads);
*(ptr+tcount) += sine; //add to other results for this time step
}
}
free(ptr);
ptr = NULL;
}
return 0;
}
这是使用以下内容编译的:
gcc -Wall -g -lm test.c
Valgrind:
valgrind --leak-check=yes ./a.out
提供:
==3028== Memcheck, a memory error detector
==3028== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==3028== Using Valgrind-3.6.0.SVN-Debian and LibVEX; rerun with -h for copyright info
==3028== Command: ./a.out
==3028==
==3028== Invalid read of size 8
==3028== at 0x8048580: main (test.c:25)
==3028== Address 0x41ca420 is 1,016 bytes inside a block of size 1,020 alloc'd
==3028== at 0x4024F20: malloc (vg_replace_malloc.c:236)
==3028== by 0x80484F8: main (test.c:15)
==3028==
==3028== Invalid write of size 8
==3028== at 0x8048586: main (test.c:25)
==3028== Address 0x41ca420 is 1,016 bytes inside a block of size 1,020 alloc'd
==3028== at 0x4024F20: malloc (vg_replace_malloc.c:236)
==3028== by 0x80484F8: main (test.c:15)
==3028==
==3028==
==3028== HEAP SUMMARY:
==3028== in use at exit: 0 bytes in 0 blocks
==3028== total heap usage: 1 allocs, 1 frees, 1,020 bytes allocated
==3028==
==3028== All heap blocks were freed -- no leaks are possible
==3028==
==3028== For counts of detected and suppressed errors, rerun with: -v
==3028== ERROR SUMMARY: 8514 errors from 2 contexts (suppressed: 14 from 7)
我对不自动管理内存的语言没有太多经验(因此这个c练习是为了学习一些知识),但我卡住了。任何帮助都将不胜感激。
这段代码应该是合成器中的一部分。在这方面它确实有效,并且给出了存储在ptr中的正确输出。
谢谢。
*(ptr+tcount) += sine;
,但是该数组从未初始化过。 - ouah