此函数从具有空格分隔值的文本文件中将值读取到2d数组中。当我运行它时，它工作得很好-但是通过Valgrind进行的内存泄漏检查确认了Xcode的怀疑，即从未两次释放“ char * splitString”，这是它的两次。我不明白这一点，考虑到我的“ char * buffer”似乎已被释放。任何帮助都非常感谢！
int** readMatrixFile(char* inFileName, int** matrix, int sizeY, int sizeX)
{
FILE* matrixFP;
int ii=0, jj=0, fileValid = 1;
char *buffer, *splitString;
const char delim[]=" \n\r";
matrixFP = fopen(inFileName, "r");
if(matrixFP != NULL)
{
/*Check if file is the same size as specified by the command line
*assumed valid until the file is checked*/
splitString = malloc(100*sizeof(char)); <------where allocated
buffer = malloc(5000*sizeof(char));
do
{
fgets(buffer, 5000, matrixFP);
jj=0;
splitString = strtok(buffer, delim);
while(splitString != NULL)
{
jj++;
splitString = strtok(NULL, delim);
}
if(jj!=sizeX)
{
fileValid = 0;
}
ii++;
} while(!feof(matrixFP));
if(ii != sizeY || buffer==NULL)
{
fileValid = 0;
}
free(splitString); <-----Appears to do nothing?
free(buffer);
if(fileValid) /*Files match to specified command line values*/
{
ii=0;
rewind(matrixFP);
matrix = (int**)malloc(sizeY * sizeof(int *));
do
{
matrix[ii] = (int*)malloc(sizeX * sizeof(int));
jj=0;
do
{
fscanf(matrixFP, "%d", &matrix[ii][jj]);
jj++;
} while(jj<sizeX);
ii++;
} while(ii<sizeY && !feof(matrixFP));
}
else
{
printf("Error: File does not match size specified by the command line\n");
}
fclose(matrixFP);
}
else
{
perror("Error: File does not exist or is invalid");
matrix = NULL;
}
return matrix;
}
和Valgrind输出：
==14087== Memcheck, a memory error detector
==14087== Copyright (C) 2002-2012, and GNU GPL'd, by Julian Seward et al.
==14087== Using Valgrind-3.8.1 and LibVEX; rerun with -h for copyright info
==14087== Command: ./pmms a b 10 3 10
==14087==
/*irrelevent program output*/
==14087==
==14087== HEAP SUMMARY:
==14087== in use at exit: 200 bytes in 2 blocks
==14087== total heap usage: 21 allocs, 19 frees, 11,680 bytes allocated
==14087==
==14087== 100 bytes in 1 blocks are definitely lost in loss record 1 of 2
==14087== at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==14087== by 0x400B55: readMatrixFile (matrix_reader.c:35)
==14087== by 0x40095E: main (pmms.c:23)
==14087==
==14087== 100 bytes in 1 blocks are definitely lost in loss record 2 of 2
==14087== at 0x4A06A2E: malloc (vg_replace_malloc.c:270)
==14087== by 0x400B55: readMatrixFile (matrix_reader.c:35)
==14087== by 0x400982: main (pmms.c:24)
==14087==
==14087== LEAK SUMMARY:
==14087== definitely lost: 200 bytes in 2 blocks
==14087== indirectly lost: 0 bytes in 0 blocks
==14087== possibly lost: 0 bytes in 0 blocks
==14087== still reachable: 0 bytes in 0 blocks
==14087== suppressed: 0 bytes in 0 blocks
==14087==
==14087== For counts of detected and suppressed errors, rerun with: -v
==14087== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 6 from 6)
首先，您要进行迭代
while(splitString != NULL)
{
...
}
所以循环完成后splitString是NULL，free(NULL)什么也不做。
第二，一旦分配了一个一百字节的内存块
splitString = malloc(100*sizeof(char)); // (*)
对splitString变量的下一个引用是赋值：
splitString = strtok(buffer, delim);
因此，无论存储在变量中的什么，它都将被覆盖！现在splitString指向该buffer块的某个位置，并且分配在的块的地址将(*)永远丢失。顺便说一句，这表明您从未使用过该块，并且实际上不需要分配它。
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我来说两句