ZDIR_PATCH(3)

💖 zdir_patch — the manual, but make it make sense 💖

okay so bestie, welcome to zdir_patch(3), straight outta the CZMQ Manual. it's a whole class for working with directory patches, and honestly? it's giving tiny-but-powerful. let's get into it 🦋

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✨ NAME ✨

zdir_patch — the class that handles working with directory patches 🎀

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🌸 SYNOPSIS 🌸

first things first, this is a stable class, and it may not change except for emergencies. periodt. 💅

//  This is a stable class, and may not change except for emergencies. It
//  is provided in stable builds.
#define ZDIR_PATCH_CREATE 1                  // Creates a new file
#define ZDIR_PATCH_DELETE 2                  // Delete a file

the two ops you can use, right there. ZDIR_PATCH_CREATE = 1 (creates a new file), ZDIR_PATCH_DELETE = 2 (deletes a file). iconic duo fr fr 👑

now the functions:

//  Create new patch
CZMQ_EXPORT zdir_patch_t *
    zdir_patch_new (const char *path, zfile_t *file, int op, const char *alias);

//  Destroy a patch
CZMQ_EXPORT void
    zdir_patch_destroy (zdir_patch_t **self_p);

//  Create copy of a patch. If the patch is null, or memory was exhausted,
//  returns null.
//  Caller owns return value and must destroy it when done.
CZMQ_EXPORT zdir_patch_t *
    zdir_patch_dup (zdir_patch_t *self);

//  Return patch file directory path
CZMQ_EXPORT const char *
    zdir_patch_path (zdir_patch_t *self);

//  Return patch file item
CZMQ_EXPORT zfile_t *
    zdir_patch_file (zdir_patch_t *self);

//  Return operation
CZMQ_EXPORT int
    zdir_patch_op (zdir_patch_t *self);

//  Return patch virtual file path
CZMQ_EXPORT const char *
    zdir_patch_vpath (zdir_patch_t *self);

//  Calculate hash digest for file (create only)
CZMQ_EXPORT void
    zdir_patch_digest_set (zdir_patch_t *self);

//  Return hash digest for patch file
CZMQ_EXPORT const char *
    zdir_patch_digest (zdir_patch_t *self);

//  Self test of this class.
CZMQ_EXPORT void
    zdir_patch_test (bool verbose);

//  Please add '@interface' section in './../src/zdir_patch.c'.

heads up bestie: that last line literally says Please add '@interface' section in './../src/zdir_patch.c'. — it's a little note to whoever's maintaining the source, not a function you call. just so we're clear 💀

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🫶 DESCRIPTION 🫶

okay so the zdir_patch class works with one patch, which says "create this file" or "delete this file" (referring to a zfile item each time). that's the whole vibe. one patch, one job, no drama 🌈

and then, direct from the source:

Please add @discuss section in ./../src/zdir_patch.c.

(yes girl, we're keeping that in. the manpage said it, so it stays ✨)

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👑 EXAMPLE 👑

this one's straight from the zdir_patch_test method, so it's the real thing, no cap:

const char *SELFTEST_DIR_RW = "src/selftest-rw";

const char *testfile = "bilbo";
const char *prefix   = "/";
char *prefixed_testfile = zsys_sprintf ("%s%s", prefix, testfile);
assert (prefixed_testfile);

// Make sure old aborted tests do not hinder us
zsys_file_delete (prefixed_testfile);

zfile_t *file = zfile_new (SELFTEST_DIR_RW, testfile);
assert (file);
zdir_patch_t *patch = zdir_patch_new (SELFTEST_DIR_RW, file, patch_create, prefix);
assert (patch);
zfile_destroy (&file);

file = zdir_patch_file (patch);
assert (file);
assert (streq (zfile_filename (file, SELFTEST_DIR_RW), testfile));
assert (streq (zdir_patch_vpath (patch), prefixed_testfile));
zdir_patch_destroy (&patch);

zstr_free (&prefixed_testfile);

#if defined (__WINDOWS__)
zsys_shutdown();
#endif

look at "bilbo" being the test file name 😭 main character energy for real. and yes, zdir_patch_new gets called with patch_create right there in the example — that's the literal token, we're keeping it exactly as written 🎀

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💜 AUTHORS 💜

the czmq manual was written by the authors in the AUTHORS file. periodt.

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🌟 RESOURCES 🌟

main web site:

report bugs to the email <zeromq-dev@lists.zeromq.org[1]>

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🎀 COPYRIGHT 🎀

Copyright (c) the Contributors as noted in the AUTHORS file. This file is part of CZMQ, the high-level C binding for 0MQ: http://czmq.zeromq.org. This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE included with the czmq distribution.

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⭐ NOTES ⭐

1. zeromq-dev@lists.zeromq.org mailto:zeromq-dev@lists.zeromq.org

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and that's the whole page bestie!! 🦋 this was CZMQ 4.2.1, dated 01/16/2026, and it's ZDIR_PATCH(3) if you ever need to find it again. slay, go patch some directories 💅✨💖