Couple of quick notes as a reminder. I’ll come back with some further notes of using a cross-compiler tool chain with Eclipse C/C++ when I have time:
Compile to object code:
as example.s -o example.o
Link to an executable:
ld -o example example.o
Writing Raspberry Pi disk images to SD cards on the Mac
Just as the dd command can be used to create a disk image of an SD card on the Mac (see here), you can use dd to write a downloaded (or backup) disk image to an SD card too:
sudo dd of=/dev/rdiskx if=/path/to/image bs=1m
where x is the disk number as shown by diskutils list.
How can you backup your SD cards for your Raspberry Pi?
Given that SD cards have a limited lifetime for writes, using an SD card for a harddrive for Pi may not be the smartest idea in terms of reliability or longevity, so asking how you back up your SD card is a good question. There’s some good answers here.
Specifically on the Mac, find out the disk number of the attached sd card with :
diskutil list
then use the dd command:
dd if=/dev/rdiskx of=/path/to/image bs=1mwhere x is the disk number listed from diskutil.
Scala: pass-by-value vs pass-by-name
pass-by-value: expressions as arguments to a function are evaluated once on passing to the function
pass-by-name: expressions are evaluated only when referenced, if they are not referenced they are not evaluated, and the expression is evaluated every time the expression is referenced
System.out.println("Calling squareCallByValue(): ")
squareCallByValue( doSomething() )
System.out.println("nCalling squareCallByName(): ")
squareCallByName( doSomething() )
System.out.println("nCalling callByNameNoReference(): ")
callByNameNoReference( doSomething() )
def doSomething() : Int = {
System.out.println("doSomething() called")
2
}
def squareCallByName(x: => Int) = {
var result = x * x
System.out.println("x in squareCallByName: " + result)
}
def callByNameNoReference(x: => Int) = {
}
def squareCallByValue(x: Int) = {
var result = x * x
System.out.println("x in squareCallByValue: " + result)
}