CODEWITHSUNDEEP
c++
george mano
george mano

Reputation: 6178

How to recognise if the .exe file needs input parameters

How can someone recognise if he needs to put input parameters for an executable in C++.

What commands should you find in a code to know which parameters are needed?

For example if you need to run it like this: hello.exe test.txt. But you dont know it.

So you run the hello executable but it needs a text file next to it. How can someone recognise in the code that this kind of parameters are needed??

EDIT: my source code has main like this int main(int argc,char *argv[]) but what exactly can the arguments be?

The only place that the argc and argv appear is at this lines. 

 #ifdef PARALLEL            
        Test.CVodeInit_parallel(states,startTime,argc,argv);
   #else
        Test.CVodeInit_serial(states,startTime);
  #endif

Upvotes: 1

Views: 1150

Answers (4)

Jeff
Jeff

Reputation: 2009

For example - if someone runs your code like this:

hello.exe test.txt

then argc will be 2, argv[0] = "hello.exe", argv[1] = "test.txt"

but if they run the code like this:

hello.exe

then argc will be 1, argv[0] = "hello.exe"

Is that the question you are asking about? Basically argc is an integer, and tells you how many strings are in the argv array

Upvotes: 1

Nicol Bolas
Nicol Bolas

Reputation: 474336

There is no simple way to take a live executable and ask it what arguments it takes. Most EXEs that take arguments have a -h or --help or /h or something similar that displays what arguments it takes. But outside of that, no.

From source code, you can kind of reconstruct its arguments. Many program use some GNU tool to parse arguments from argv, so you'll need to be familiar with that to understand what it's doing. Boost.ProgramOptions is an alternative that some people use. And others just parse the arguments manually, so you have to walk the code and watch what it pulls out of argv.

The only place that the argc and argv appear is at this lines.

Then you must look at the implementation of Test.CVodeInit_parallel to know what arguments it takes.

Upvotes: 0

davka
davka

Reputation: 14692

parameters are passed to the program as parameters of the main function, which should look like this:

int main(int argc, char** argv)

where argc is the number of parameters and argv is an array of strings containing the actual arguments.

So check in the code whether these parameters are handled.

NOTE: the main function can also look like this:

int main()

which is legal but mean that the program does not expect, or handles, parameters.

Upvotes: 0

Bernd Elkemann
Bernd Elkemann

Reputation: 23560

You write "in the code" but you are asking about the ".exe". It is unclear whether you have access to the source-code or want to derive it from the raw binary.

In the former case you would have to take a look at the main()/WinMain()-function (or equivalent entry-point), the latter case would probably be impractical / too difficult as it involves disassembly and heuristics.

Upvotes: 0

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