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signal(int signum, void (*handler)(int))

signal

sigaction(int sig, const struct sigaction *restrict act, struct sigaction *restrict oact)

#!/bin/bash -p

if [ $# -eq 0 ]; then
    echo "Usage: $(basename $0) " 1>&2
    exit 1
fi

while [ -d /proc/$1 ]; do sleep 0.5; done

function find_lowest_subprocess() {
    local -i parent=$1
    local pids
    typeset -a pids

    pids=($(pgrep -P $parent))
    while ((${#pids[@]} > 0)); do
        if ((${#pids[@]} > 1)); then
            parent=${pids[0]}
            local i=0
            while ((i < ${#pids[@]})); do
                local sub=$(pgrep -P ${pids[$i]})
                [[ -n $sub ]] && parent=$sub
                ((i=i + 1))
            done
        else
            parent=$pids
        fi
        pids=($(pgrep -P $parent))
    done
    echo $parent
}

• Apple Mac OS X Human Interface Guidelines
• Microsoft Vista 'Design Guidelines'
• Palm OS Application Design Guidelines Pre PalmOS 6
• Java Look and Feel Guidelines (Version 2)
• Gnome Human Interface Guidelines (Gnome-HIG)
• KDE UI Standards

function find_lowest_subprocess() {
        local -i parent=$1
        local pids
        typeset -a pids

        pids=$(pgrep -P $parent)
        while [[ -n "$pids" ]]; do
                if (( ${#pids[@]} > 1 )); then
                        local i=0
                        while (( i < ${#pids[@]} )); do
                                local sub=$(pgrep -P ${pids[$i]})
                                [[ -n $sub ]] && parent=$sub
                                ((i=i + 1))
                        done
                else
                        parent=$pids
                fi
                pids=$(pgrep -P $parent)
        done
        echo $parent
}

(1) The [[ operator is not the same as the program /bin/[[ as a program you need to still use double quotes around the variables to be expanded; thus defeating the reason for having them in the first place.

For Example:

	# file="/tmp/let me go"
	# touch "$file"
	# [[ -e $file ]] && echo "There"

Yields [Busybox]:

	[[: me: unknown operand

- as $file is word split before handing it to the command [[

Yields [bash]:

	There

- due to $file not being split when passed to the test -e.

Again, the quantity of run levels is determined by the provenance of the Operating System - for example the machine I'm currently working on(Ubuntu) claims a run-level of 2, while the fedora core desktop I've just checked claims a run-level of 5. Solaris makes thing really fun by informing you that tour run-level is a legacy state that you should stop considering to be useful, after all it's about the services that you have enabled, not the run-level.

This can be useful for extracting the lowest numbered element of a bit set. Given a 2's complement binary integer value x, (x&-x) is the least significant 1 bit. The reason this works is that it is equivalent to (x & ((~x) + 1)); any trailing zero bits in x become ones in ~x, adding 1 to that carries into the following bit, and AND with x yields only the flipped bit... the original position of the least significant 1 bit.

Alternatively, since (x&(x-1)) is actually x stripped of its least significant 1 bit, the least significant 1 bit is also (x^(x&(x-1))).

A branchless, lookup-free, alternative to code like if (a<b) x=c; else x=d; is ((((a-b) >> (WORDBITS-1)) & (c^d)) ^ d). This code assumes that the shift is signed, which, of course, C does not promise.

Given 2's complement integer values x and y, the minimum can be computed without any branches as x+(((y-x)>>(WORDBITS-1))&(y-x)). Logically, this works because the shift by (WORDBITS-1) replicates the sign bit to create a mask -- be aware, however, that the C language does not require that shifts are signed even if their operands are signed, so there is a potential portability problem. Additionally, one might think that a shift by any number greater than or equal to WORDBITS would have the same effect, but many instruction sets have shifts that behave strangely when such shift distances are specified.

Of course, maximum can be computed using the same trick: x-(((x-y)>>(WORDBITS-1))&(x-y)).

Normally, a dual-linked circular list would contain both previous and next pointer fields and the current position in the list would be identified by a single pointer. By using two current pointers, one to the node in question and the other to the one just before/after it, it becomes possible to store only a single pointer value in each node. The value stored in each node is the XOR of the next and previous pointers that normally would have been stored in each node. Decoding is obvious.

Unfortunately, using this trick in C is awkward because the XOR operation is not defined for pointers.

My old, unreliable mobile phone died a couple of days ago, and I needed to buy a replacement. I'm not able to upgrade my phone for another 2 months so I decided to buy a pay-as-you-go phone and just slip my SIM into it (same network, no issues with locking). People who know me, will understand that I have a liking for flip-phones, so I went for the Motorola V3 (Razr). Aargh! christ, but the phonebook is the biggest piece of shit I've ever come across. I understand this misbegotten need to have the phone book maintain some compatibility with the SIM, but for christ's sake, they need to get their act together on this. Practically every contact in my phone book has two entries, in fact most have 3. On the motorola phone book every contact is a separate entry on the person list. This means I have to wade through 2+ entries per person to scroll from one person to the next. Factor in that I store people's full names on the phone, in surname order, wading through the 9 Shanahan's in the book takes a long time. It always integrates the SIM contacts onto the phone book. There is no visible option to disable this 'feature' (my SIM contacts always were a backup of my phone entries), so I end up with loads of duplicates (or purge my SIM). I can't send my entire contact details to someone, I have to send it piece by piece. It shows the email addresses interspersed with the phone numbers which is pointless most of the time.

The next complaint is really a bit of a click-fascist thing. You know what I mean by this - it just seems to take an extra click or two to perform some tasks. Just enough to annoy perceptibly.

Then there's the syncing software. Following the really annoying splash screen - slow, irritating and serving no purpose, we are presented with a rendering of my phone on the bottom right corner of the screen, a bunch of icons and no idea what does what without mousing over one of the icons and seeing what it does, based on the tooltip! Come on people, tooltips cannot replace text! Apparently I can dial numbers from the number pad (never would have guessed at that). The only way to pop up the menu is to hit a box that's about 20 pixels square, replicating the menu button on the phone itself. Too small to hit easily, and there is no keyboard navigation, unless you can guess at the magic hotkeys. Most of the hard work is farmed off to other applications, none of which share details of the current state of the phone (contacts, calendar), each sub-application launch causes the data to be re-read, which takes ~30 seconds each. None of these sub-applications are keyboard navigable (bugbear of mine). Quitting the application requires either clicking on the really small off switch, or doing the acme Alt+F4 close the window trick. Practically everything visual about this application could do with a rewrite.
On the plus side, it does synchronize, which is it's primary role, but I just wish it wasn't so annoying about it.

Badly implemented phonebook aside, practically everything else about the phone is good. It's small, neat and call quality is great. I've not tested the bluetooth functionality very much so I can't say either way on it. Over all, I'd consider it a good replacement phone, but unless something good happens with the phone book, I'm not planning on buying another Motorola phone in the forseeable future after this one.

Now if only I could make my own phone book. I wonder if it's even possible on these kinds of phone. Maybe I should check this out.

AttachThreadInput(GetWindowThreadProcessId(
  GetForegroundWindow(), NULL),
  GetCurrentThreadId(), TRUE);

SetForegroundWindow(hWnd);

AttachThreadInput(GetWindowThreadProcessId(
  GetForegroundWindow(), NULL),
  GetCurrentThreadId(), FALSE);

  IDBInitialize *pIDBInitialize = NULL;
  IDataInitialize *pIDataInitialize = NULL;
  IDBPromptInitialize *pIDBPromptInitialize = NULL;
  LPOLESTR strConn;

  CoCreateInstance(CLSID_DataLinks, NULL, CLSCTX_INPROC_SERVER, IID_IDataInitialize,
    (void **)&pIDataInitialize);

  CoCreateInstance(CLSID_DataLinks, NULL, CLSCTX_INPROC_SERVER,
    IID_IDBPromptInitialize, (void **)&pIDBPromptInitialize);

  pIDBPromptInitialize->PromptDataSource(NULL, 0,
    DBPROMPTOPTIONS_PROPERTYSHEET, 0, NULL, NULL, IID_IDBInitialize,
    (IUnknown **)&pIDBInitialize);

  pIDBInitialize->Initialize();

  pIDataInitialize->GetInitializationString(pIDBInitialize, true, &strConn);

  MSDASC.DataLinks oDL = new MSDASC.DataLinksClass();
  ADODB.Connection conn = new ADODB.ConnectionClass();
  conn.ConnectionString = "Provider=sqloledb";
  object oConn = (object)conn;
  oDL.PromptEdit(ref oConn);
  OleDbConnection xconn = new OleDbConnection(conn.ConnectionString);
  xconn.Open();

Registry Keys that needed permission changes:
HKCR\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}
HKCR\CLSID\{50BAEEDA-ED25-11D2-B97B-000000000000}
HKCR\CLSID\{50BAEEDB-ED25-11D2-B97B-000000000000}
HKCR\VFPOLEDB
HKCR\VFPOLEDB.1
HKCR\Vfpoledb.ConnectionPage
HKCR\Vfpoledb.ConnectionPage.1
HKCR\VFPOLEDB.ConnectionPage
HKCR\VFPOLEDB.ConnectionPage.1

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Classes]

[HKEY_CURRENT_USER\Software\Classes\CLSID]

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}]
"OLEDB_SERVICES"=dword:ffffffff
@="VFPOLEDB"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\ExtendedErrors]
@="Extended Error Service"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\ExtendedErrors\{50BAEEDA-ED25-11D2-B97B-000000000000}]
@="VFPOLEDB Error Lookup"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\Implemented Categories]

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\Implemented Categories\{D267E19A-0B97-11D2-BB1C-00C04FC9B532}]
@=""

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\InprocServer32]
"ThreadingModel"="Both"
@="C:\\Program Files\\Common Files\\System\\ole db\\vfpoledb.dll"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\OLE DB Provider]
@="Microsoft OLE DB Provider for Visual FoxPro"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\ProgID]
@="VFPOLEDB.1"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\TypeLib]
@="{50BAEECA-ED25-11D2-B97B-000000000000}"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEED9-ED25-11D2-B97B-000000000000}\VersionIndependentProgID]
@="VFPOLEDB"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEEDA-ED25-11D2-B97B-000000000000}]
@="VFPOLEDB Error Lookup"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEEDA-ED25-11D2-B97B-000000000000}\InprocServer32]
"ThreadingModel"="both"
@="C:\\Program Files\\Common Files\\System\\ole db\\vfpoledb.dll"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEEDA-ED25-11D2-B97B-000000000000}\ProgID]
@="VFPOLEDB.ErrorLookup.1"

[HKEY_CURRENT_USER\Software\Classes\CLSID\{50BAEEDA-ED25-11D2-B97B-000000000000}\VersionIndependentProgID]
@="VFPOLEDB.ErrorLookup"

[HKEY_CURREN