Have you experienced malloc failing a lot? How do you test to ensure error handling code paths work as expected?
Have you read 'notes' section of Linux malloc manpage? It says:
By default, Linux follows an optimistic memory allocation strategy. This means that when malloc() returns non-NULL there is no guarantee that the memory really is available. In case it turns out that the system is out of memory, one or more processes will be killed by the OOM killer.
#include <stdlib.h>
#include <stdio.h>
#include <sys/resource.h>
const int SIZE = 64*1024*1024;
int main() {
char *buffer = NULL;
struct rlimit r;
/* Limit all memory to 1024 bytes */
r.rlim_cur = 1024;
r.rlim_max = 1024;
if (setrlimit(RLIMIT_AS, &r) == -1 ) {
perror("setrlimit(RLIMIT_AS) error\n");
exit(EXIT_FAILURE);
}
if ( (buffer = malloc( sizeof(long) * SIZE) ) == NULL) {
perror("malloc() failed\n");
exit(EXIT_FAILURE);
}
free(buffer);
printf("Malloc worked\n");
return 0;
}
%cc fail.c
%./a.out
malloc() failed
: Cannot allocate memory
It's tedious work.
Edit. It is impossible for malloc to fail (at least on linux) [1]. Seems rather pointless checking for something that can’t happen.
Actually the real issue here is that you should be aware that on some systems malloc might fail and not segfault.