SD_ID128_TO_STRING(3)         sd_id128_to_string         SD_ID128_TO_STRING(3)

NAME
       sd_id128_to_string, SD_ID128_TO_STRING, SD_ID128_STRING_MAX,
       sd_id128_to_uuid_string, SD_ID128_TO_UUID_STRING,
       SD_ID128_UUID_STRING_MAX, sd_id128_from_string - Format or parse
       128-bit IDs as strings

SYNOPSIS
       #include <systemd/sd-id128.h>

       #define SD_ID128_STRING_MAX 33U

       #define SD_ID128_UUID_STRING_MAX 37U

       #define SD_ID128_TO_STRING(id) ...

       #define SD_ID128_TO_UUID_STRING(id) ...

       char
                                *sd_id128_to_string(sd_id128_t id, char s[static SD_ID128_STRING_MAX]);

       char
                                  *sd_id128_uuid_string(sd_id128_t id, char s[static SD_ID128_UUID_STRING_MAX]);

       int sd_id128_from_string(const char *s, sd_id128_t *ret);

DESCRIPTION
       sd_id128_to_string() formats a 128-bit ID as a character string. It
       expects the ID and a string array capable of storing 33 characters
       (SD_ID128_STRING_MAX). The ID will be formatted as 32 lowercase
       hexadecimal digits and be terminated by a NUL byte.

       SD_ID128_TO_STRING() is a macro that wraps sd_id128_to_string() and
       passes an appropriately sized buffer as second argument, allocated as
       C99 compound literal. Each use will thus implicitly acquire a suitable
       buffer on the stack which remains valid until the end of the current
       code block. This is usually the simplest way to acquire a string
       representation of a 128-bit ID in a buffer that is valid in the current
       code block.

       sd_id128_to_uuid_string() and SD_ID128_TO_UUID_STRING() are similar to
       these two functions/macros, but format the 128bit values as RFC4122
       UUIDs, i.e. a series of 36 lowercase hexadeciaml digits and dashes,
       terminated by a NUL byte.

       sd_id128_from_string() implements the reverse operation: it takes a 33
       character string with 32 hexadecimal digits (either lowercase or
       uppercase, terminated by NUL) and parses them back into a 128-bit ID
       returned in ret. Alternatively, this call can also parse a 37-character
       string with a 128-bit ID formatted as RFC UUID. If ret is passed as
       NULL the function will validate the passed ID string, but not actually
       return it in parsed form.

       Note that when formatting and parsing 36 character UUIDs this is done
       strictly in Big Endian byte order, i.e. according to RFC4122[1] Variant
       1 rules, even if the UUID encodes a different variant. This matches
       behaviour in various other Linux userspace tools. It's probably wise to
       avoid UUIDs of other variant types.

       For more information about the "sd_id128_t" type see sd-id128(3). Note
       that these calls operate the same way on all architectures, i.e. the
       results do not depend on endianness.

       When formatting a 128-bit ID into a string, it is often easier to use a
       format string for printf(3). This is easily done using the
       SD_ID128_FORMAT_STR and SD_ID128_FORMAT_VAL() macros. For more
       information see sd-id128(3).

RETURN VALUE
       sd_id128_to_string() always succeeds and returns a pointer to the
       string array passed in.  sd_id128_from_string() returns 0 on success,
       in which case ret is filled in, or a negative errno-style error code.

NOTES
       These APIs are implemented as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO
       systemd(1), sd-id128(3), printf(3)

NOTES
        1. RFC4122
           https://tools.ietf.org/html/rfc4122

systemd 252                                              SD_ID128_TO_STRING(3)

Czas wygenerowania: 0.00037 sek.

Created with the man page lookup class by Andrew Collington.
Based on a C man page viewer by Vadim Pavlov
Unicode soft-hyphen fix (as used by RedHat) by Dan Edwards
Some optimisations by Eli Argon
Caching idea and code contribution by James Richardson

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