Problem with argc

Why does an if stament that checks to see if argc is less than 4 get entered in my program?? I passed exactly 4 arguments. The three arguments after the program name all are surrounded with quotes. argv[0] is the program name, argv[1] is the input file path, argv[2] is a list of search strings, and argv[3] is a list of replace strings.

Here is the if statement that is being entered:

Code:

---

if (argc < 4) {
  cerr<< "Error! You must pass the path to the file which contains\n"
              "stuff you want to replace as the first argument to the program,\n"
              "after the program name, and also pass two other arguments: the\n"
              "list of search strings, and the list of replace strings, in that\n"
              "order.\n\nPress Enter to access Help and quit.\n\n";
  cin.get();
  help();
  return 1;
}

---

And here is the arguments I pass to the program:

Code:

---

ReplaceStrsInLines "/home/USERNAME/Documents/C_html4_elements.h" "[string;desc]" "[C_html_element;element]"

---

And argv[0] ReplaceStrsInLines
And argv[1] "/home/USERNAME/Documents/C_html4_elements.h"
And argv[2] "[string;desc]"
and argv[3] "[C_html_element;element]"

I don't know how you add but that adds up to 4 arguments to me. And since 4 is not less than 4?

Jim

Quote:

---

Originally Posted by jimblumberg

And argv[0] ReplaceStrsInLines
And argv[1] "/home/USERNAME/Documents/C_html4_elements.h"
And argv[2] "[string;desc]"
and argv[3] "[C_html_element;element]"

I don't know how you add but that adds up to 4 arguments to me. And since 4 is not less than 4?

Jim

---

Precisely.
That's why I don't understand why the if statement which checks to see if argc < 4 is entered when I have exactly 4 arguments.

Here is the entire output when I run it with the above arguments:

Quote:

---

Thank you for running ReplaceStrsInLines.
This program was created for the purpose of reading a file,
finding every line of the file which includes each search string
passed to the program, and replacing the bits of text in those lines
with the replace strings you pass to the program.

Please press Enter to continue.

Processing...please wait.
Error! You must pass the path to the file which contains
stuff you want to replace as the first argument to the program,
after the program name, and also pass two other arguments: the
list of search strings, and the list of replace strings, in that
order.

Press Enter to access Help and quit.


sh: desc]: not found
sh: element: not found

Press Enter to continue.

---

Hmm...and I just realized I forgot to output help there. I just call the function, but I dont output the return value.

Also note that I don't know what that last part of the output is. I don't have it in my source code.
It must be an error message outputted by a system function which is triggered by some event.

Have you considered using a debugger?

Quote:

---

Originally Posted by kmdv

Have you considered using a debugger?

---

I used a debugger on it, but it didn't detect any problems.

So you're trying to tell us that you set a breakpoint on the line with if (argc <4) and ran it in the debugger, checked the values of argc and argv, they were as you expected above, and yet you entered that block?

Not believing it.

Quote:

---

Originally Posted by Programmer_P

Why does an if stament that checks to see if argc is less than 4 get entered in my program?? I passed exactly 4 arguments.

---

Weird.

Code:

---

1 #include <iostream>
 2
 3 int main(int argc, char** argv)
 4 {
 5    if (argc < 4)
 6        std::cout << "Less than 4 arguments" << std::endl;
 7
 8    return 0;
 9 }

---

Output:

Code:

---

stuff$ a.out 2
Less than 4 arguments
stuff$ a.out 2 3
Less than 4 arguments
stuff$ a.out 2 3 4
stuff$ a.out 2 3 4 5
stuff$

---

Works as expected. I guess I'll try something closer to your code to see if that somehow makes a difference:

Code:

---

1 #include <iostream>
 2 using namespace std;
 3
 4 int main(int argc, char** argv)
 5 {
 6    if (argc < 4) {
 7        cerr<< "Error! You must pass the path to the file which contains\n"
 8                  "stuff you want to replace as the first argument to the program,\n"
 9                  "after the program name, and also pass two other arguments: the\n"
10                  "list of search strings, and the list of replace strings, in that\n"
11                  "order.\n\nPress Enter to access Help and quit.\n\n";
12        cin.get();
13        //help();
14        return 1;
15    }
16
17    return 0;
18 }

---

Output:

Code:

---

stuff$ g++ argc2.cpp -o ReplaceStrsInLines
stuff$ ReplaceStrsInLines "/home/USERNAME/Documents/C_html4_elements.h" "[string;desc]" "[C_html_element;element]"
stuff$

---

That's what I thought. Could you do some experimentation and maybe post a complete program in the form of a short version of your code that also has the problem you described?

Quote:

---

Originally Posted by rags_to_riches

So you're trying to tell us that you set a breakpoint on the line with if (argc <4) and ran it in the debugger, checked the values of argc and argv, they were as you expected above, and yet you entered that block?

Not believing it.

---

Hey only a week or two ago at work I saw gdb enter "if (shouldBeInMap) { (stuff) }" when gdb also said shouldBeInMap was false. I don't think the executable was actually doing that, but the debugger said the program was in there.

Quote:

---

Originally Posted by rags_to_riches

So you're trying to tell us that you set a breakpoint on the line with if (argc <4) and ran it in the debugger, checked the values of argc and argv, they were as you expected above, and yet you entered that block?

Not believing it.

---

Well, no, I didn't set any breakpoints until after reading your post.
Then I did, and the debugger says argc is 3, but that still doesn't make any sense seeing as I passed 4 arguments to the program, not 3.

Quote:

---

Originally Posted by Mozza314

Weird.

Code:

---

1 #include <iostream>
 2
 3 int main(int argc, char** argv)
 4 {
 5    if (argc < 4)
 6        std::cout << "Less than 4 arguments" << std::endl;
 7
 8    return 0;
 9 }

---

Output:

Code:

---

stuff$ a.out 2
Less than 4 arguments
stuff$ a.out 2 3
Less than 4 arguments
stuff$ a.out 2 3 4
stuff$ a.out 2 3 4 5
stuff$

---

Works as expected. I guess I'll try something closer to your code to see if that somehow makes a difference:

Code:

---

1 #include <iostream>
 2 using namespace std;
 3
 4 int main(int argc, char** argv)
 5 {
 6    if (argc < 4) {
 7        cerr<< "Error! You must pass the path to the file which contains\n"
 8                  "stuff you want to replace as the first argument to the program,\n"
 9                  "after the program name, and also pass two other arguments: the\n"
10                  "list of search strings, and the list of replace strings, in that\n"
11                  "order.\n\nPress Enter to access Help and quit.\n\n";
12        cin.get();
13        //help();
14        return 1;
15    }
16
17    return 0;
18 }

---

Output:

Code:

---

stuff$ g++ argc2.cpp -o ReplaceStrsInLines
stuff$ ReplaceStrsInLines "/home/USERNAME/Documents/C_html4_elements.h" "[string;desc]" "[C_html_element;element]"
stuff$

---

That's what I thought. Could you do some experimentation and maybe post a complete program in the form of a short version of your code that also has the problem you described?

---

Sure.
Give me a few minutes to put together a shorter version which has this problem.

Quote:

---

Originally Posted by Programmer_P

Well, no, I didn't set any breakpoints until after reading your post.
Then I did, and the debugger says argc is 3, but that still doesn't make any sense seeing as I passed 4 arguments to the program, not 3.

---

Check the values of argv[0], argv[1], argv[2]. It's highly unusual, but I think it may be possible to run a program without passing it its own name as argv[0]. If your ide has this unusual but possible behaviour, that could explain it.

Try this program:

Code:

---

1 #include <iostream>
 2 using namespace std;
 3
 4 int main(int argc, char** argv)
 5 {
 6    for (int i = 0; argv[i] != NULL; ++i)
 7        cout << argv[i] << ' ';
 8
 9    cout << endl;
10
11    return 0;
12 }

---

Quote:

---

Originally Posted by Mozza314

Check the values of argv[0], argv[1], argv[2]. It's highly unusual, but I think it may be possible to run a program without passing it its own name as argv[0]. If your ide has this unusual but possible behaviour, that could explain it.

Try this program:

Code:

---

1 #include <iostream>
 2 using namespace std;
 3
 4 int main(int argc, char** argv)
 5 {
 6    for (int i = 0; argv[i] != NULL; ++i)
 7        cout << argv[i] << ' ';
 8
 9    cout << endl;
10
11    return 0;
12 }

---

---

Hmm...good idea.
I added the following for loop to my code, before that if statement which checks to see if argc < 4:

Code:

---

for (int i = 0; argv[i] != NULL; ++i)
        cout<< "argv[" << i << "] is:\n" << argv[i] << '\n' <<endl;

---

Now the output was:

Quote:

---

PROGRAM_INTRODUCTION

Please press Enter to continue.

Processing...please wait.
argv[0] is:
/home/USERNAME/Documents/Programming_Projects/ReplaceStrsInLines/bin/Debug/ReplaceStrsInLines

argv[1] is:
/home/USERNAME/Documents/C_html4_elements.h

argv[2] is:
[string

OUTPUT_OF_IF_STATEMENT

---

The semicolon is obviously being interpreted by the shell as the end of that command. Try escaping it.

Spending a few hours to learn to use the debugger will save you (and us) countless hours of grief and frustration.

Quote:

---

Originally Posted by rags_to_riches

The semicolon is obviously being interpreted by the shell as the end of that command. Try escaping it.

Spending a few hours to learn to use the debugger will save you (and us) countless hours of grief and frustration.

---

Why would it be doing that?
I thought the shell uses the space character as the end of an argument, except for the last argument, though it ignores spaces inside of quotes.
And I'm assuming by "escaping" it you mean pass this to the program:

Code:

---

ReplaceStrsInLines "/home/USERNAME/Documents/C_html4_elements.h" "[string\;desc]" "[C_html_element\;element]"

---

?

Also note that the program worked ok with the following arguments:

Code:

---

ReplaceStrsInLines "/home/USERNAME/Documents/C_html4_elements.h" "[map<string, vector_str_t>;supported_attrs_list]" "[map<S_browser, TYPE_attrs>]"

---

though there is a semicolon in argv[2]. So why would it do that if the shell is interpreting the semicolon as the end of an argument??

Side note: I do use the debugger. However, it wasn't very helpful with this problem, was it?

No the way to escape any of the special characters, which include (from memory) [, ], ;, <space>, >, <, |, and & is to surround the argument that uses them in double quotes.

TBH I have been trying to reproduce your problem, and I can't no matter what I do. So I have to suspect you're doing something extremely wrong.

Compile main with the strictest definition possible:

Code:

---

int main ( const int argc, const char *const *argv )

---

We shall see what happens. Maybe you modify these variables in the program.

Quote:

---

Originally Posted by whiteflags

No the way to escape any of the special characters, which include (from memory) [, ], ;, <space>, >, <, |, and & is to surround the argument that uses them in double quotes.

---

..which I did, but it still enters that if statement.

Quote:

---

TBH I have been trying to reproduce your problem, and I can't no matter what I do. So I have to suspect you're doing something extremely wrong.

Compile main with the strictest definition possible:

Code:

---

int main ( const int argc, const char *const *argv )

---

We shall see what happens. Maybe you modify these variables in the program.

---

That's ridiculous. I certainly do not. I do not modify them in any way. I just retrieve the argv[] strings after the checks on argc have been made, and store them inside C++ strings.

I'll a post a short version of my program...ahh, heck. No, I wont. I'll post the whole thing, so y'all can look over it. Its only one source file, and its not that long, and it'll save typing, and will ensure I didn't miss anything important.

Ok, here is the file:

ReplaceStrsInLines.cpp

Works fine for me as well, with or without the escaping, on Mac OS X.

Code:

---

/pp "/home/USERNAME/Documents/C_html4_elements.h" "[string;desc]" "[C_html_element;element]"
Thank you for running ReplaceStrsInLines.
This program was created for the purpose of reading a file,
finding every line of the file which includes each search string
passed to the program, and replacing the bits of text in those lines
with the replace strings you pass to the program.

Please press Enter to continue.

Processing...please wait.
argv[0] is:
./pp

argv[1] is:
/home/USERNAME/Documents/C_html4_elements.h

argv[2] is:
[string;desc]

argv[3] is:
[C_html_element;element]

---

Quote:

---

That's ridiculous. I certainly do not. I do not modify them in any way. I just retrieve the argv[] strings after the checks on argc have been made, and store them inside C++ strings.

---

I'm really sorry if you were offended, but we are heading into ridiculous territory.

Apart from things that I obviously don't have, so your program wouldn't open any files, I get this:

Quote:

---

Thank you for running ReplaceStrsInLines.
This program was created for the purpose of reading a file,
finding every line of the file which includes each search string
passed to the program, and replacing the bits of text in those lines
with the replace strings you pass to the program.

Please press Enter to continue.

Processing...please wait.
argv[0] is:
C:\Documents and Settings\Owner\My Documents\sandbox\bin\Debug\sandbox.exe

argv[1] is:
/home/USERNAME/Documents/C_html4_elements.h

argv[2] is:
[string;desc]

argv[3] is:
[C_html_element;element]

input_filepath is: /home/USERNAME/Documents/C_html4_elements.h
search_strs_str is: [string;desc]
replace_strs_str is: [C_html_element;element]
Error! The file you passed could not be opened.
Please verify your filepath, and try again.

Exiting out...

Process returned 1 (0x1) execution time : 2.422 s
Press any key to continue.

---

Can't reproduce the problem. What else can you tell us?

Would you be willing to use a workaround? Put these arguments into a file, and work with the file instead. You could make the filepath the argument. That way we can get away from console parsing or whatever is broken here.

Quote:

---

Originally Posted by rags_to_riches

Works fine for me as well, with or without the escaping, on Mac OS X.

Code:

---

/pp "/home/USERNAME/Documents/C_html4_elements.h" "[string;desc]" "[C_html_element;element]"
Thank you for running ReplaceStrsInLines.
This program was created for the purpose of reading a file,
finding every line of the file which includes each search string
passed to the program, and replacing the bits of text in those lines
with the replace strings you pass to the program.

Please press Enter to continue.

Processing...please wait.
argv[0] is:
./pp

argv[1] is:
/home/USERNAME/Documents/C_html4_elements.h

argv[2] is:
[string;desc]

argv[3] is:
[C_html_element;element]

---

---

Ok, well I'm sure the shell in Mac OS X is a lot different than the shell in Ubuntu 8.10.
That's probably why you can't reproduce the problem that I'm getting.

Quote:

---

Originally Posted by whiteflags

I'm really sorry if you were offended, but we are heading into ridiculous territory.

---

No worries. I understand that you couldn't have known that I didn't modify those variables. Its just that I'm getting a little frustrated with this problem now, as I'm making little headway, and have been working on it for several hours now, and it makes no sense at all.

Quote:

---

Apart from things that I obviously don't have, so your program wouldn't open any files, I get this:



Can't reproduce the problem. What else can you tell us?

Would you be willing to use a workaround? Put these arguments into a file, and work with the file instead. You could make the filepath the argument. That way we can get away from console parsing or whatever is broken here.

---

What OS are you using?
Since its probably a shell problem, the probable reason neither of you can reproduce my problem is the fact that both of you are using a different shell than I am.

I may put the arguments in a file, but it seems like a poor way of doing things, and inconveniences the user.

Quote:

---

What OS are you using?
Since its probably a shell problem, the probable reason neither of you can reproduce my problem is the fact that both of you are using a different shell than I am.

---

Right! Well, I'm going to mentally kick myself for not providing that earlier.

I use Windows XP SP3's command prompt.

Ok...this is interesting.
When I run my program through the Ubuntu Gnome-Terminal with the same arguments, it works fine. It only produces the problem I posted about when I run it through xterm by pressing the Run button in the Code::Blocks IDE.

So it must be a bug in xterm. I already posted about the issue on the Ubuntu forums.
Hopefully the guys over there will take care of it.

I was able to duplicate your results. The semicolon seems to be a special character for the the xterm bash shell in Linux. If you change the semicolon to a comma it seems to work ok.

Jim

Quote:

---

Originally Posted by jimblumberg

I was able to duplicate your results. The semicolon seems to be a special character for the the xterm bash shell in Linux. If you change the semicolon to a comma it seems to work ok.

Jim

---

Well, I had it to use commas originally, but then I needed to change a line which had a comma as part of the search string, so I decided to change the commas to semicolons instead. So now you want me to change it back?? :)
I decided a semicolon is more useful, as you would most likely not want to replace a semicolon, as that is the terminating character for nearly all programming statement lines in most languages.
And anyway, even if it is a special character in xterm, it seems like to me that wrapping the argument with double quotes should make it ignore it, and treat it as part of the argument. Another thing, someone at the Ubuntu forums just suggested that I should replace all " characters with ' characters instead, but I just tried that, and still the same problem, so I guess the guy didn't know what he was talking about.

EDIT: Ok, someone else just posted, and suggested that the problem is not xterm but is the cb_console_runner. So I guess I'm off now to go harass the Code::Blocks developers about this issue... :p

Quote:

---

Originally Posted by whiteflags

I should probably tackle this in parts.

If the user is yourself: why are you uncomfortable with files? Programmers write files of all kinds every day. It's not "poor" unless your text editor is just awful.

---

The user is myself, but its not about comfortableness. Its about speed. :p
I dislike the thought of having to type out a different file first each time I want to run ReplaceStrsInLines, which seeing as I'm using it on my other programming projects, which I'm working on in almost daily basis, would be often.
Instead, I want to be able to just run the program, and worry about what I have to pass to it as I'm typing the command in the console.

I already found that thread you linked to, btw, and subscribed to it. Interesting behavior of Notepad, I might add. I knew about the line-wrap problem already, but the other things mentioned were new to me.

Quote:

---

If the user is anyone else: why would they be comfortable with command line arguments? I don't know an average joe who wants to run utilities this way; perhaps they do when there is a problem to fix.

That's just my observation of human nature.

---

Who knows...MY observations of people tell me that there is another level of person between "programmer" and "average joe", and that is the type of person who doesn't program, but likes using CLI-based programs over GUI. These type of people are often semi-geeks who can't be bothered to learn a programming language, but are interested in the command line nonetheless. Such people can be found on the Ubuntu forums nearly every day, just as a small example.

Quote:

---

And while you do that, Mr. Steel Balls, you need an interim solution.

---

Really? :) Are you sure about that?
I don't know...I kind of was thinking along the lines of pointing out the problem, and letting the developers of the software find the solution, since they are after all, the ones who are responsible for the problem I'm experiencing.

EDIT: Or maybe I misunderstood what you meant...if you meant that I need a solution to use while I'm trying to get the other resolved, I've already got one: just run the program through the Gnome-Terminal, and forget about running it through Code::Blocks for now.

Quote:

---

Really? Are you sure about that?

---

Well that whole post is probably not one of my brighter moments, but nothing precludes you from keeping this version which produces the problem and working around it for the meantime.

Well, someone at the Code::Blocks forums gave me a workaround:

Just surround the arguments with doublequotes, and surround the doublequotes with single quotes, which works. So now I am able to run the program through Code::Blocks, and pass the same arguments that broke it with only doublequotes.