xenial (3) sd_id128_from_string.3.gz

NAME

       sd_id128_to_string, sd_id128_from_string - Format or parse 128-bit IDs as strings

SYNOPSIS

       #include <systemd/sd-id128.h>

       char *sd_id128_to_string(sd_id128_t id, char s[33]);

       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. The ID will be formatted as 32 lowercase hexadecimal digits and be
       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.

       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

       The sd_id128_to_string() and sd_id128_from_string() interfaces are available 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)