sd_id128_to_string
systemd
Developer
Lennart
Poettering
lennart@poettering.net
sd_id128_to_string
3
sd_id128_to_string
sd_id128_from_string
Format or parse 128-bit IDs as strings
#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-id1283. 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
printf3. This
is easily done using the
SD_ID128_FORMAT_STR and
SD_ID128_FORMAT_VAL() macros. For
more information see
sd-id1283.
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-config1
file.
See Also
systemd1,
sd-id1283,
printf3