helloc$valgrind ./a.out
==123254== Memcheck, a memory error detector
==123254== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==123254== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright
info
==123254== Command: ./a.out
==123254==
enter string (EOF) to quit): test1
enter string (EOF) to quit): test2
enter string (EOF) to quit): (all done)
test1
test2
==123254==
==123254== HEAP SUMMARY:
==123254== in use at exit: 0 bytes in 0 blocks
==123254== total heap usage: 6 allocs, 6 frees, 2,084 bytes allocated
==123254==
==123254== All heap blocks were freed -- no leaks are possible
==123254==
==123254== For lists of detected and suppressed errors, rerun with: -s
==123254== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
-----------------------------------------------------------------------------------------------------------------
simple c program source code:
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define MAXC 1024
int main(void){
char buf[MAXC],**arr = NULL;
size_t nstr = 0; /* counter for number of string stored */
for(;;){
size_t len; /* var to hold length of string after n removeal */
fputs("enter string (EOF) to quit): ",stdout);
if(!fgets(buf,MAXC,stdin)){
puts("(all done)\n");
break;
}
buf[len = strcspn(buf,"\r\n")] = 0;
/*always realloc using temp pointer to avoid mem-leak on reallco
failure*/
void *tmp = realloc(arr,(nstr+1) * sizeof *arr);
if(!tmp){
perror("realloc-tmp");
break;
}
arr = tmp;
if(!(arr[nstr] = malloc(len + 1))){
perror("malloc-arr[str]");
break;
}
memcpy(arr[nstr++], buf,len + 1);
}
for(size_t i = 0; i < nstr; i++){
puts(arr[i]);
free(arr[i]);
}
free(arr);
return 0;
}
---------------------------------------------
New to C, I am not sure the following:
total heap usage: 6 allocs, 6 frees, 2,084 bytes allocated
I guess 6 allocs is 3 times mallocs called plus 3 times puts function
called?
But I don't know where 2084 comes from.
--
I recommend David Deutsch's <<The Beginning of Infinity>>
Jian
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