当我将元素放入数组时，我正在尝试重新分配结构数组，但是我一直收到realloc stderr。结构数组最终将包含235,000个元素。当我将初始起始大小设置为100,000时，尝试重新分配时会收到stderr。如果我将初始起始大小设置为300,000，则不会给出错误，因为它永远不会到达realloc语句。
#define _XOPEN_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#include <string.h>
#define BUFFERLEN 200
#define START_SIZE 100000
#define GROW 1000
#define TRUE 1
#define FALSE 0
typedef struct{
char *forw;
char *back;
} word;
typedef struct{
char *entry;
} single_words;
FILE *words;
/*-------------Function Prototypes------------*/
void reverse(char* string, char* revstr, int len);
int search_struct(char* find, word* words, int length);
int compare(const void* eventa, const void* eventb);
int length(char* string);
int main(void)
{
char *buffer;
int letter_index[26];
char alpha[] = "abcdefghijklmnopqrstuvwxyz";
int i=0, found = FALSE, strlen=0, letter=0;
word *word_storage;
single_words *output_storage;
int num_words = 0, size = 0;
int num_output = 0, output_size = 0;
/*buffer for the input strings of the words in the input file*/
buffer = (char*) malloc (sizeof(char)*BUFFERLEN);
if(!buffer){
fprintf(stderr, "Error in buffer string mem alloc\n");
exit(1);
}
/*Initializing the array of structs to store the forward and reverse of each word*/
word_storage = (word*) malloc (sizeof(word)*START_SIZE);
if(!word_storage){
fprintf(stderr, "Error in word_storage string mem alloc\n");
exit(1);
}
size = START_SIZE;
/*Initializing the array of structs for the output*/
output_storage = (single_words*) malloc (sizeof(single_words)*START_SIZE);
if(!output_storage){
fprintf(stderr, "Error in output_storage mem alloc\n");
exit(1);
}
output_size = START_SIZE;
/*Set the letter index 0(which is a) to the first character*/
letter_index[0] = 0;
words = fopen("words", "r");
/*Read the words(forward and reverse) in from stdin into the word_storage*/
while(fgets(buffer, BUFFERLEN, words) != NULL){
buffer = strtok(buffer, "\n");
strlen = length(buffer);
if (num_words < size){
/*Allocate memory for the forward and reverse strings*/
word_storage[num_words].forw = (char *) malloc (sizeof(char) * strlen);
if(!word_storage[num_words].forw){
free(word_storage[num_words].forw);
fprintf(stderr, "word_storage forward string malloc was unsuccessful");
exit(1);
}
word_storage[num_words].back = (char *) malloc (sizeof(char) * strlen);
if(!word_storage[num_words].back){
free(word_storage[num_words].back);
fprintf(stderr, "word_storage forward string malloc was unsuccessful");
exit(1);;
}
/*Store the forward and reverse in the strings*/
strncpy(word_storage[num_words].forw, buffer, strlen);
reverse(word_storage[num_words].forw, word_storage[num_words].back, strlen);
printf("%d: %s %s\n", num_words, word_storage[num_words].forw, word_storage[num_words].back);
/*Increment the letter if it changes*/
if(word_storage[num_words].forw[0] != alpha[letter]){
letter++;
letter_index[letter] = num_words + 1;
}
num_words++;
}
else{
/*Increase the size of word_storage*/
word_storage = (word*) realloc (word_storage, sizeof(word) * size * GROW);
if(!word_storage){
free(word_storage);
fprintf(stderr, "Error in word_storage realloc string mem realloc\n");
exit(1);
}
size = size * GROW;
}
}
return 0;
}
重新分配错误发生在这里：
word_storage = (word*) realloc (word_storage, sizeof(word) * size * GROW);
if(!word_storage){
free(word_storage);
fprintf(stderr, "Error in word_storage realloc string mem realloc\n");
exit(1);
}
size = size * GROW;
最佳答案
因此，最初将size设置为START_SIZE，即100,000。然后，当您用尽它时，您尝试分配sizeof(word) * size * GROW字节。 sizeof(word)大概是16个字节；我们知道size是100000，而GROW是1000。这样算出足够的空间来容纳100,000,000个条目，您说您将使用235,000。分配似乎有点慷慨。
100,000,000个条目的总空间为1,600,000,000字节。这似乎很多，尽管如今许多台式机都可以处理。但是realloc失败似乎并不奇怪。
也许您应该使GROW更加合理，例如2。
顺便说一句，一旦确定word_storage为NULL，调用free(word_storage)就没有意义了。因为free(NULL)是无操作的，所以它没有害处，但出于相同的原因也没有好处。
关于c - 结构数组内存重新分配stderr，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/19206005/