Nothing funny, just bit manipulation and accessing a big array. The functions are all similar and all display the same results; here's one example:
The system is 32-bit Xubuntu 8.10 on a quad-core Phenom II.
As I said before, the results are consistent. When I call
the time for the first, fourth, and seventh times are fast, the times for the third, sixth, and ninth times are slow, etc.
---------- Post updated at 01:23 AM ---------- Previous update was at 01:18 AM ----------
Quote:
Originally Posted by jim mcnamara
I happen not to like the static declaration of functions for a variety of reasons except in certain instances-- But that is very probably not the cause of this problem.
I don't do it much. If you have advice on better ways to do it, feel free to expound (or give a link!).
having problems using scp in that during peak hours it appears to time out.
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hi everyone. If you have a function created in your code and you want to find out how long it takes for it to run you can use a struct called gettimeofday().
so lets say we have a function like this
int myfunction (int r)
{
/*some math calculations*/
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}
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i have a very big script i have that i'd like to add a timeout to.
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I have two shell scripts, one written with xargs for parallel processing (p1) and the other written in old school way (p3) .
when I execute them, i get the below values.
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real 0m25.36s
user 0m0.32s
sys 0m0.80s
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real 0m23.25s
user 0m6.20s
sys ... (4 Replies)
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Hello and thanks in advance for any help anyone can offer me
I'm trying to learn the find command and thought I was understanding it... Apparently I was wrong. I was doing compound searches and I started getting weird results with the -size test. I was trying to do a search on a 1G file owned by... (14 Replies)
Discussion started by: bodisha
14 Replies
LEARN ABOUT CENTOS
sd_id128_format_str
SD-ID128(3) sd-id128 SD-ID128(3)NAME
sd-id128, sd_id128_t, SD_ID128_MAKE, SD_ID128_CONST_STR, SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL, sd_id128_equal - APIs for processing
128-bit IDs
SYNOPSIS
#include <systemd/sd-id128.h>
pkg-config --cflags --libs libsystemd-id128
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[1] but use a simpler string format. These functions impose no structure on the used IDs,
much unlike OSF UUIDs or Microsoft GUIDs, but are fully compatible with those types of IDs.
See sd_id128_to_string(3), sd_id128_randomize(3) and sd_id128_get_machine(3) for more information about the implemented functions.
A 128-bit ID is implemented as the following union type:
typedef union sd_id128 {
uint8_t bytes[16];
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 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:
#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_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":
int main(int argc, char *argv[]) {
puts(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 printf(3) format string, as shown in the following
example:
int main(int argc, char *argv[]) {
sd_id128_t id;
id = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
printf("The ID encoded in this C file is " SD_ID128_FORMAT_STR ".
", SD_ID128_FORMAT_VAL(id));
return 0;
}
Use sd_id128_equal() to compare two 128-bit IDs:
int main(int argc, char *argv[]) {
sd_id128_t a, b, c;
a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
b = SD_ID128_MAKE(f2,28,88,9c,5f,09,44,15,9d,d7,04,77,58,cb,e7,3e);
c = a;
assert(sd_id128_equal(a, c));
assert(!sd_id128_equal(a, b));
return 0;
}
Note that new, randomized IDs may be generated with journalctl(1)'s --new-id option.
NOTES
These APIs are implemented as a shared library, which can be compiled and linked to with the "libsystemd-id128" pkg-config(1) file.
SEE ALSO systemd(1), sd_id128_to_string(3), sd_id128_randomize(3), sd_id128_get_machine(3), printf(3), journalctl(1), sd-journal(7), pkg-config(1),
machine-id(5)NOTES
1. RFC 4122
https://tools.ietf.org/html/rfc4122
systemd 208SD-ID128(3)