pipe_enomem.c

/* $Id: pipe_enomem.c,v 1.3 2020/03/07 21:02:04 kostik Exp kostik $ */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

struct pipepair {
	int pp[2];
};

static struct pipepair *p;

int
main(void)
{
	int error, pp[2];
	size_t i, k, nsz, sz;
	char x;

	sz = 1024;
	p = calloc(sz, sizeof(struct pipepair));
	if (p == NULL) {
		fprintf(stderr, "calloc: %s\n", strerror(errno));
		exit(1);
	}

	for (i = 0;; i++) {
		if (pipe(pp) == -1) {
			printf("created %zd pipes. syscall error %s\n",
			    i, strerror(errno));
			break;
		}
		if (i >= sz) {
			nsz = sz * 2;
			p = reallocf(p, nsz * sizeof(struct pipepair));
			if (p == NULL) {
				fprintf(stderr, "reallocf: %s\n",
				    strerror(errno));
				exit(1);
			}
			memset(p + sz, 0, (nsz - sz) * sizeof(struct pipepair));
			sz = nsz;
		}
		p[i].pp[0]= pp[0];
		p[i].pp[1]= pp[1];
	}

	x = 'a';
	for (k = 0; k < i; k++) {
		error = write(p[k].pp[1], &x, 1);
		if (error == -1)
			printf("pipe %zd fds %d %d error %s\n",
			    k, p[k].pp[0], p[k].pp[1], strerror(errno));
		else if (error == 0)
			printf("pipe %zd fds %d %d EOF\n",
			    k, p[k].pp[0], p[k].pp[1]);
	}
}