sys.argv is indeed a list of strings. Use the int() function to turn a string to a number, provided the string can be converted. You need to assign the result, however: num1 = int(argv[1]) num2 = int(argv[2]) or simply use: num1, num2 = int(num1), int(num2) You did call int() but ignored the return value.
From the Standard: 5.1.2.2.1 Program startup … — argv[argc] shall be a null pointer. So, yes; argv is null terminated
In 10.6, KERN_PROCARGS2 is available: https://gist.github.com/770696 This way is used from ps, procfs on MacFUSE, etc.
With the exec class of calls, you specify the program name and program executable separately so you can set it to NULL then. But that quote is actually from the ISO standard (possibly paraphrased) and that standard covers a awfully large range of execution environments from the smallest micro-controller to the latest z10 Enterprise-class mainframe. … Read more
Because you did from os import *, you are (accidenally) using os.open, which indeed requires an integer flag instead of a textual “r” or “w”. Take out that line and you’ll get past that error.
The arguments argc and argv of main is used as a way to send arguments to a program, the possibly most familiar way is to use the good ol’ terminal where an user could type cat file. Here the word cat is a program that takes a file and outputs it to standard output (stdout). … Read more
These methods are suited for servers with a lot of java processes running, and where you need a quick way of finding the correct jvm (not using jps.) For applications, I suppose launch4j or another wrapper is the way to go. On unix, If you are launching from a shell sript (at least for bash … Read more
If you want to have your arguments C style (array of arguments + number of arguments) you can use $@ and $#. $# gives you the number of arguments. $@ gives you all arguments. You can turn this into an array by args=(“$@”). So for example: args=(“$@”) echo $# arguments passed echo ${args[0]} ${args[1]} ${args[2]} … Read more
Guesswork (even educated guesswork) is fun but you really need to go to the standards documents to be sure. For example, ISO C11 states (my emphasis): If the value of argc is greater than zero, the string pointed to by argv[0] represents the program name; argv[0][0] shall be the null character if the program name … Read more
argv and argc are how command line arguments are passed to main() in C and C++. argc will be the number of strings pointed to by argv. This will (in practice) be 1 plus the number of arguments, as virtually all implementations will prepend the name of the program to the array. The variables are … Read more