From the C11 standard draft N1570, §5.1.2.2.1/2: The parameters argc and argv and the strings pointed to by the argv array shall be modifiable by the program, and retain their last-stored values between program startup and program termination. They are modifiable. That means they are not string literals. But be careful: the upper citation only … Read more
This is not related to your code but to the shell that starts it. In most shells, !! is shorthand for the last command that was run. When you use double quotes, the shell allows for history expansion (along with variable substitution, etc.) within the string, so when you put !! inside of a double-quoted … Read more
You can convert the arguments to integers using int() import sys a = int(sys.argv[1]) b = int(sys.argv[2]) print a, b print a+b input: python mySum.py 100 200 output: 100 200 300
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
Here’s what the C standard (n1256) says: 5.1.2.2.1 Program startup… 2 If they are declared, the parameters to the main function shall obey the following constraints: The value of argc shall be nonnegative. argv[argc] shall be a null pointer. If the value of argc is greater than zero, the array members argv[0] through argv[argc-1] inclusive … Read more
Yes. The non-null pointers in the argv array point to C strings, which are by definition null terminated. The C Language Standard simply states that the array members “shall contain pointers to strings” (C99 §5.1.2.2.1/2). A string is “a contiguous sequence of characters terminated by and including the first null character” (C99 §7.1.1/1), that is, … 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
From the Standard: 5.1.2.2.1 Program startup … — argv[argc] shall be a null pointer. So, yes; argv is null terminated
I believe you want the shlex module. >>> import shlex >>> shlex.split(‘-o 1 –long “Some long string”‘) [‘-o’, ‘1’, ‘–long’, ‘Some long string’]
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.