libpmemlog

The PMDK repository on GitHub is the ultimate source of information on PMDK from release 2.0! For all questions and to submit eventual issues please follow to that repository. The PMDK documentation collected here should be valid up to the 1.13.1 release but is maintained only on a best-effort basis and may not reflect the latest state of the art.

Discontinuation of the project

The libpmemlog project will no longer be maintained by Intel.

  • Intel has ceased development and contributions including, but not limited to, maintenance, bug fixes, new releases, or updates, to this project.
  • Intel no longer accepts patches to this project.
  • If you have an ongoing need to use this project, are interested in independently developing it, or would like to maintain patches for the open source software community, please create your own fork of this project.
  • You will find more information here.

The libpmemlog library

libpmemlog implements a pmem-resident log file.

This library is provided for cases requiring an append-mostly file to record variable length entries. Most developers will find higher level libraries like libpmemobj to be more generally useful.

Man pages that contains a list of the Linux interfaces provided:

Man pages that contains a list of the Windows interfaces provided:

NOTE

NOTICE: The libpmemlog library is deprecated since PMDK 1.13.0 release and was removed in the PMDK 2.0.0 release.

libpmemlog Examples

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

/* size of the pmemlog pool -- 1 GB */
#define	POOL_SIZE ((off_t)(1 << 30))

/*
 * printit -- log processing callback for use with pmemlog_walk()
 */
int
printit(const void *buf, size_t len, void *arg)
{
	fwrite(buf, len, 1, stdout);
	return 0;
}

int
main(int argc, char *argv[])
{
	const char path[] = "/pmem-fs/myfile";
	PMEMlogpool *plp;
	size_t nbyte;
	char *str;

	/* create the pmemlog pool or open it if it already exists */
	plp = pmemlog_create(path, POOL_SIZE, 0666);

	if (plp == NULL)
	    plp = pmemlog_open(path);

	if (plp == NULL) {
		perror(path);
		exit(1);
	}

	/* how many bytes does the log hold? */
	nbyte = pmemlog_nbyte(plp);
	printf("log holds %zu bytes\n", nbyte);

	/* append to the log... */
	str = "This is the first string appended\n";
	if (pmemlog_append(plp, str, strlen(str)) < 0) {
		perror("pmemlog_append");
		exit(1);
	}
	str = "This is the second string appended\n";
	if (pmemlog_append(plp, str, strlen(str)) < 0) {
		perror("pmemlog_append");
		exit(1);
	}

	/* print the log contents */
	printf("log contains:\n");
	pmemlog_walk(plp, 0, printit, NULL);

	pmemlog_close(plp);
}

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