diff --git a/man/sd-id128.xml b/man/sd-id128.xml index b6e50a559e..566cc2b595 100644 --- a/man/sd-id128.xml +++ b/man/sd-id128.xml @@ -40,6 +40,69 @@ #include <systemd/sd-id128.h> + + + SD_ID128_ALLF + + + SD_ID128_NULL + + + SD_ID128_CONST_STR(id) + + + SD_ID128_FORMAT_STR + + + SD_ID128_FORMAT_VAL(id) + + + SD_ID128_MAKE(v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, vA, vB, vC, vD, vE, vF) + + + SD_ID128_MAKE_STR(v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, vA, vB, vC, vD, vE, vF) + + + SD_ID128_MAKE_UUID_STR(v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, vA, vB, vC, vD, vE, vF) + + + SD_ID128_UUID_FORMAT_STR + + + + int sd_id128_equal + sd_id128_t a + sd_id128_t b + + + + int sd_id128_is_null + sd_id128_t id + + + + int sd_id128_is_allf + sd_id128_t id + + + + int sd_id128_in_setv + sd_id128_t id + va_list ap + + + + int sd_id128_in_set_sentinel + sd_id128_t id + … + SD_ID128_NULL + + + + int sd_id128_in_set + sd_id128_t id + … + @@ -51,20 +114,13 @@ Description - sd-id128.h provides APIs to process and generate 128-bit ID values. The - 128-bit ID values processed and generated by these APIs are a generalization of OSF UUIDs as defined by - RFC 4122 but use a simpler string format. These - functions impose no structure on the used IDs, much unlike OSF UUIDs or Microsoft GUIDs, but are mostly - compatible with those types of IDs. + sd-id128.h provides APIs to generate, convert, and compare 128-bit ID values. + The 128-bit ID values processed and generated by these APIs are a generalization of OSF UUIDs as defined + by RFC 4122 but use a simpler string format. + These functions impose no structure on the used IDs, much unlike OSF UUIDs or Microsoft GUIDs, but are + mostly compatible with those types of IDs. - See - sd_id128_to_string3, - sd_id128_randomize3 - and - sd_id128_get_machine3 - for more information about the implemented functions. - A 128-bit ID is implemented as the following union type: @@ -73,30 +129,28 @@ uint64_t qwords[2]; } sd_id128_t; - This union type allows accessing the 128-bit ID as 16 - separate bytes or two 64-bit words. It is generally safer to - access the ID components by their 8-bit array to avoid endianness - issues. This union is intended to be passed call-by-value (as - opposed to call-by-reference) and may be directly manipulated by + This union type allows accessing the 128-bit ID as 16 separate bytes or two 64-bit words. It is + generally safer to access the ID components by their 8-bit array to avoid endianness issues. This union + is intended to be passed by value (as opposed to pass-by-reference) and may be directly manipulated by clients. A couple of macros are defined to denote and decode 128-bit IDs: - SD_ID128_MAKE() may be used to denote a - constant 128-bit ID in source code. A commonly used idiom is to - assign a name to a 128-bit ID using this macro: + SD_ID128_MAKE() is used to write a constant ID in source code. A commonly used + idiom is to assign a name to an ID using this macro: #define SD_MESSAGE_COREDUMP SD_ID128_MAKE(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1) - SD_ID128_NULL may be used to refer to the 128-bit ID consisting of only - NUL bytes (i.e. all bits off). + SD_ID128_NULL defines an ID consisting of only NUL bytes + (i.e. all bits off). - SD_ID128_ALLF may be used to refer to the 128-bit ID consisting of only - 0xFF bytes (i.e. all bits on). + SD_ID128_ALLF defines an ID consisting of only 0xFF bytes + (i.e. all bits on). - SD_ID128_MAKE_STR() is similar to SD_ID128_MAKE(), but creates a - const char* expression that can be conveniently used in message formats and such: + SD_ID128_MAKE_STR() is similar to SD_ID128_MAKE(), but + creates a const char* expression that can be conveniently used in message formats and + such: #include <stdio.h> #define SD_MESSAGE_COREDUMP_STR SD_ID128_MAKE_STR(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1) @@ -105,18 +159,16 @@ int main(int argc, char **argv) { puts("Match for coredumps: MESSAGE_ID=" SD_MESSAGE_COREDUMP_STR); } - SD_ID128_CONST_STR() may be used to - convert constant 128-bit IDs into constant strings for output. The - following example code will output the string - "fc2e22bc6ee647b6b90729ab34a250b1": + SD_ID128_CONST_STR() converts constant IDs into constant strings for + output. The following example code will output the string "fc2e22bc6ee647b6b90729ab34a250b1": int main(int argc, char *argv[]) { puts("Match for coredumps: %s", SD_ID128_CONST_STR(SD_MESSAGE_COREDUMP)); } - SD_ID128_FORMAT_STR and SD_ID128_FORMAT_VAL() may - be used to format a 128-bit ID in a - printf3 - format string, as shown in the following example: + SD_ID128_FORMAT_STR and SD_ID128_FORMAT_VAL() is used to + format an ID in a printf3 format + string, as shown in the following example: int main(int argc, char *argv[]) { sd_id128_t id; @@ -136,7 +188,7 @@ int main(int argc, char **argv) { best to avoid UUIDs of other variants, in order to avoid unnecessary ambiguities. All 128-bit IDs generated by the sd-id128 APIs strictly conform to Variant 1 Version 4 UUIDs, as per RFC 4122. - Use sd_id128_equal() to compare two 128-bit IDs: + sd_id128_equal() compares two 128-bit IDs: int main(int argc, char *argv[]) { sd_id128_t a, b, c; @@ -148,18 +200,22 @@ int main(int argc, char **argv) { return 0; } - Use sd_id128_is_null() to check if an 128-bit ID consists of only - NUL bytes: + sd_id128_is_null() checks if an ID consists of only NUL + bytes: assert(sd_id128_is_null(SD_ID128_NULL)); - Similarly, use sd_id128_is_allf() to check if an 128-bit ID consists of only + Similarly, sd_id128_is_allf() checks if an ID consists of only 0xFF bytes (all bits on): assert(sd_id128_is_allf(SD_ID128_ALLF)); - For convenience, sd_id128_in_set() takes a list of IDs and - returns true if any are equal to the first argument: + sd_id128_in_set_sentinel() takes a list of IDs and returns true if the first + argument is equal to any of the subsequent arguments. The argument list is terminated by an + SD_ID128_NULL sentinel, which must be present. + + sd_id128_in_set() is a convenience function that takes a list of IDs and + returns true if the first argument is equal to any of the subsequent arguments: int main(int argc, char *argv[]) { sd_id12_t a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07); @@ -175,18 +231,25 @@ int main(int argc, char **argv) { sd_id128_in_set() is defined as a macro over - sd_id128_in_set_sentinel(), adding the SD_ID128_NULL - sentinel. Since sd_id128_in_set_sentinel() uses SD_ID128_NULL - as the sentinel, SD_ID128_NULL cannot be otherwise placed in the argument list. - + sd_id128_in_set_sentinel(), adding the SD_ID128_NULL sentinel + automatically. Since sd_id128_in_set_sentinel() uses + SD_ID128_NULL as the sentinel, SD_ID128_NULL cannot be + otherwise placed in the argument list. sd_id128_in_setv() is similar to sd_id128_in_set_sentinel(), but takes a struct varargs argument. - Note that new, randomized IDs may be generated with + New randomized IDs may be generated with systemd-id1281's new command. + + See + sd_id128_to_string3, + sd_id128_randomize3 + and + sd_id128_get_machine3 + for information about other implemented functions.