QB_LOG_FR...NAL_SOURCE(3)

💖 QB_LOG_FR...NAL_SOURCE(3) 💖

okay so bestie, we're in the libqb Programmer's Manual today and this one is literally the ✨bridge✨ function — it's how you pull logs in from other code (think libraries 👀) that hand you a callback stuffed with their own log messages. no cap.

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🌸 NAME 🌸

qb_log_from_external_source — this function is to import logs from other code (like libraries) that provide a callback with their logs. fr fr that's the whole job description 💅

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✨ SYNOPSIS ✨

#include <qb/qblog.h>

void qb_log_from_external_source(
    const char   *function,  /* originating function name */
    const char   *filename,  /* originating filename */
    const char   *format,    /* format string */
    uint8_t       priority,  /* this takes syslog priorities. */
    uint32_t      lineno,    /* file line number */
    /*
     * this is a uint32_t that you can use with
     * qb_log_tags_stringify_fn_set() to "tag" a log message with a feature or sub-system then you can use
     * "%g" in the format specifer to print it out.
     */
    uint32_t      tags,
    ...
);

like, look at that signature. it ate. 🎀

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🦋 PARAMS 🦋

• function — originating function name
• filename — originating filename
• format — format string
• priority — this takes syslog priorities.
• lineno — file line number
• tags — this is a uint32_t that you can use with qb_log_tags_stringify_fn_set() to "tag" a log message with a feature or sub-system then you can use "%g" in the format specifer to print it out.

(null)

yeah girl, that last line is just... sitting there. iykyk. moving on 🙈

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💜 DESCRIPTION 💜

this is the function you call when some other chunk of code — a library, a dependency, a mysterious little guy you didn't write — gives you a callback full of logs and you wanna funnel those straight into libqb. iconic behavior honestly 👑

📌 NOTE 📌

okay so heads up bestie: the performance of this will not impress you 😭 because the filtering is done on each log message, not beforehand. so try doing basic pre-filtering. like, protect your CPU. she's trying her best. 🫶

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🌈 SEE ALSO 🌈

the whole extended family, in all their glory:

• qb_log_filter_fn_set(3)
• qb_log_from_external_source_va2(3)
• qb_log_thread_start(3)
• qb_log_target_user_data_get(3)
• qb_log_tags_stringify_fn_set(3)
• qb_log_file_reopen(3)
• qb_log_fini(3)
• qb_log_callsites_dump(3)
• qb_log_ctl2(3)
• qb_log_target_user_data_set(3)
• qb_log_target_format(3)
• qb_log_thread_priority_set(3)
• qb_log_facility2int(3)
• qb_log_callsites_register(3)
• qb_log_filter_ctl2(3)
• qb_log_file_close(3)
• qb_log_format_set(3)
• qb_log_real_(3)
• qb_log_from_external_source_va(3)
• qb_log_callsite_get(3)
• qb_log_blackbox_write_to_file(3)
• qb_log_real_va_(3)
• qb_log_blackbox_print_from_file(3)
• qb_log_facility2str(3)
• qb_log_callsite_get2(3)
• qb_log_ctl(3)
• qb_log_filter_ctl(3)
• qb_log_custom_close(3)
• qb_log_init(3)
• qb_log_file_open(3)
• qb_log_custom_open(3)

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👑 COPYRIGHT 👑

Copyright (c) 2017 Red Hat, Inc.

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and that's the whole page, bestie!! 💖 this dropped as part of libqb with the 2025-09-16 date on it, and you read the entire thing, so slay. go log something. periodt. ✨🦋💅