systemd/man/journal-enumerate-fields.c

/* SPDX-License-Identifier: MIT-0 */

#include <errno.h>
#include <stdio.h>
#include <systemd/sd-journal.h>

int main(int argc, char *argv[]) {
  sd_journal *j;
  const char *field;
  int r;

  r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY);
  if (r < 0) {
    fprintf(stderr, "Failed to open journal: %s\n", strerror(-r));
    return 1;
  }
  SD_JOURNAL_FOREACH_FIELD(j, field)
    printf("%s\n", field);
  sd_journal_close(j);
  return 0;
}
man: change license of examples to MIT-0 Quoting Richard Fontana in [1]: CC0 has been listed by Fedora as a 'good' license for code and content (corresponding to allowed and allowed-content under the new system). We plan to classify CC0 as allowed-content only, so that CC0 would no longer be allowed for code. Over a long period of time a consensus has been building in FOSS that licenses that preclude any form of patent licensing or patent forbearance cannot be considered FOSS. CC0 has a clause that says: "No trademark or patent rights held by Affirmer are waived, abandoned, surrendered, licensed or otherwise affected by this document." (The trademark side of that clause is nonproblematic from a FOSS licensing norms standpoint.) The regular Creative Commons licenses have similar clauses. For the case of our documentation snippets, patent issues do not matter much. But it is always nicer to have a license that is considerred acceptable without any further considerations. So let's change the license to the (now recommended replacement) MIT-0. [1] https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/NO7KGDNL5GX3KCB7T3XTGFA3QPSUJA6R/ Using 'git blame -b' and 'git log -p --follow', I identified the following folks as having made non-trivial changes to those snippets: Lennart Poettering Tom Gundersen Luca Bocassi Zbigniew Jędrzejewski-Szmek Thomas Mühlbacher Daan De Meyer I'll ask for confirmation in the pull request. 2022-10-26 06:02:14 +00:00			`/* SPDX-License-Identifier: MIT-0 */`
man: use external .c files for three examples This way it's much easier to test that the code compiles without issues. It's also easier to edit the code. Indentation in one of the examples is reduced to two spaces. This is what we use in man pages to make them fit on screen better. 2022-10-10 07:18:26 +00:00
man: recommend %m over strerror() The need to set errno is very very ugly, but at least it is thread-safe and works correctly. Using strerror() is likely to be wrong, so let's not recommend that. People who do a lot of logging would provide use some wrapper that sets errno like we do, so nudge people towards %m. I tested that all the separate .c files compile cleanly. 2022-10-07 14:19:21 +00:00			`#include <errno.h>`
man: use external .c files for three examples This way it's much easier to test that the code compiles without issues. It's also easier to edit the code. Indentation in one of the examples is reduced to two spaces. This is what we use in man pages to make them fit on screen better. 2022-10-10 07:18:26 +00:00			`#include <stdio.h>`
			`#include <systemd/sd-journal.h>`

			`int main(int argc, char *argv[]) {`
			`sd_journal *j;`
			`const char *field;`
			`int r;`

			`r = sd_journal_open(&j, SD_JOURNAL_LOCAL_ONLY);`
			`if (r < 0) {`
man/examples: use strerror() instead of %m 2024-04-02 18:40:05 +00:00			`fprintf(stderr, "Failed to open journal: %s\n", strerror(-r));`
man: use external .c files for three examples This way it's much easier to test that the code compiles without issues. It's also easier to edit the code. Indentation in one of the examples is reduced to two spaces. This is what we use in man pages to make them fit on screen better. 2022-10-10 07:18:26 +00:00			`return 1;`
			`}`
			`SD_JOURNAL_FOREACH_FIELD(j, field)`
			`printf("%s\n", field);`
			`sd_journal_close(j);`
			`return 0;`
			`}`