I'm new in OS X.
I'm writing programs with UNIX system calls in Xcode.
I'd like to debug program with argument vector line by line.
But I don't know how I can put argument value into **argv.
Assume that executable file has the name 'a.out', which I want to debug line by line in Xcode. All I have to do is let the program be initially set argv to the following.
argv[0] = "./a.out"
argv[1] = "ls"
argv[2] = "foo"
argv[3] = "-l"
What Should I do? Thank you in advance.
Do you mean you want to pass in arguments to your program when you debug? If so, click on the name of your target in the drop-down menu next to Run and Stop, go down to "Edit Scheme...", and then click on the arguments tab. You can add arguments to pass in there.
Related
I am trying to debug a C++ program using GDB. I have set 15 breakpoints. Most of the breakpoints are in different files. After the first 5 breakpoints, it became difficult to remember what line of code any given breakpoint refers to.
I struggle quite a bit simply trying to recall what a given breakpoint refers to. I find this quite distracting. I was wondering if there is a way to tell gdb to display code around a certain breakpoint.
Something like this - $(gdb) code 3 shows 30 lines of code around breakpoint 3. Is this possible today. Could you please show me how?
I run gdb in tui mode, and I also keep emacs open to edit my source files.
You can use gdb within emacs.
In emacs, type M-x gdb, after entering the name of the executable, type M-x gdb-many-windows. It brings up an IDE-like interface, with access to debugger, locals, source, input/output, stack frame and breakpoints.
You can find a reference and snapshot here.
I don't think you can do it exactly like this in gdb as such, but it can be scripted in gdb python.
This crude script should help:
import gdb
class Listbreak (gdb.Command):
""" listbreak n Lists code around breakpoint """
def __init__ (self):
super(Listbreak, self).__init__ ("listbreak", gdb.COMMAND_DATA)
def invoke (self, arg, from_tty):
printed = 0
for bp in gdb.breakpoints():
if bp.number == int(arg[0]):
printed = 1
print ("Code around breakpoint " + arg[0] + " (" + bp.location + "):")
gdb.execute("list " + bp.location)
if printed == 0:
print ("No such breakpoint")
Listbreak()
Copy this to listbreak.py, source it in gdb (source listbreak.py), then use it like this:
listbreak 2
I am trying to call an executable with qprocess and pass some arguments which might (and most probably will) contain spaces (not all of them).
The executable is a python script that has been packaged with Py2exe. The python script uses optparse to parse the arguments.
If I call the py2exe.exe in cmd.exe the call is like this:
pythonExecutable.exe -aarg_a -barg_b -c"path with spaces" -darg_d
A call like this will be successful.
I want to do this through a Qt application using Qprocess, but I can't find a way to do it because Qprocess will strip any quotes("") leaving the arguments broken wherever spaces appear.
I seem to be missing something, can anyone help with this issue?
that won't be much of an issue if u use the QProcess in a more proper way
QString program = "pythonExecutable.exe";
QStringList arguments;
arguments <<"-aarg_a"<< "-barg_b"<< "-c\"path with spaces\""<< "-darg_d";
QProcess *myProcess = new QProcess(parent);
myProcess->start(program, arguments);
normaly when u have arguments with space and do't need a " symbol
you just have to pass the argument in a QStringList
QString program = "pythonExecutable.exe";
QStringList arguments;
arguments <<"a"<< "path with spaces";
QProcess *myProcess = new QProcess(parent);
myProcess->start(program, arguments);
this program is a modified version of example program listed in the Qt docs Here
This is a bit long, so bear with me!
I'm having a bit of trouble working with a Haskell program, that I have to use as part of a uni project. For reference, it's Casper.
So, you're supposed to execute a script, which is actually a Bash script to invoke Hugs interpreter like this:
exec $HUGSBIN/hugs $HUGSARGS +p"Casper> " $FILES
Where $FILES points to a Main.lhs file.
After this, I need to invoke a function "compile" with a path to a file, in the interpreter.
I need to perform the above in a scripted manner. I need this automated because I'm writing a program that will call on Casper in the background.
So I compiled the .lhs file. Now I want to execute the "compile" function but I have no idea how this is done. I try:
./Main compile <a path>
from the command line but it returns me an error about a file "test" not found. Upon investigation, I see these lines in the Main.lhs file:
>main :: String -> IO()
>main = compile "test"
>compile :: String -> IO()
>compile s = catch (compile0 False s) handler
[...snipped]
The 2nd line solves this question. Now my question is, how do I invoke the "compile" function and pass a path to it after I have compiled main.lhs? From the interpreter, I just type "compile " and it works, but I can't get the same to work after compiling the main.lhs and executing from the command line? Any ideas why? Is there any way I can script Hugs if all else fails?
Thank you for any assistance!
You may access the command-line arguments passed to a Haskell program via getArgs. For example, it sounds like you want a main function that does something like this:
>main = do
> args <- getArgs
> case args of
> [] -> putStrLn "What file did you want me to compile?"
> [filename] -> compile filename
> _ -> putStrLn "I only compile one file at a time."
Modify to taste.
Replace main with
main = getArgs >>= \(arg1:_) -> compile arg1
This will pass the first command line argument (arg1) to compile instead of "test", and ignore the rest (_). You may need to add
import System
or
import System.Environment
I can't remember what is needed in hugs for this.
I have a problem with the GetCommandLine() API.
It usually returns the executable name followed by a space and arguments. As documentation says, the first token may not have the complete path to the image and blah blah blah.
I never had problems until now that I used CreateProcess with lpApplicationName not NULL.
If I use:
CreateProcess(NULL, "\"c:\\myexe.exe\" param1 param2", ...)
GetCommandLine returns "c:\myexe.exe param1 param2" as expected.
But if I use:
CreateProcess("C:\myexe.exe", "param1 param2")
GetCommandLine returns only "param1 param2".
How do I know if the executable name is given on the command line if another application launches mine?
Also, MFC startup code assumes that the first token on the command line is the executable name and skips it. But if you launch a MFC application with the second CreateProcess API example, MFC's code will skip the first argument.
Not your problem. It's the job of the other application to construct the command line properly. You should simply assume that the first argument is an executable name as expected and skip over it.
I have a workaround which can be helpful in a case like this.
I guess we always be able to check how our module was been started.
In this case we should check first argument.
I will write code because I have some problem with English.
Here two ways:
The first case. we can compare module name with first command line argument.
something like this:
const TCHAR* csCommandLine = ::GetCommandLine();
// Attention!!! the first symbol can be quete
if (*csCommandLine == _T('\"'))
csCommandLine++;
TCHAR sModuleFileName[MAX_PATH];
DWORD dwModuleFileName = ::GetModuleFileName(NULL, sModuleFileName, MAX_PATH);
if (dwModuleFileName && !_tcsncmp(csCommandLine, sModuleFileName, dwModuleFileName)) {
// The command line contains the module name.
}
The second case. we can try to get file attributes for the first command line argument
something like this:
// Attention!!! don't use it case if you are going to pass a file path in command line arguments.
int nArgc;
LPTSTR* szArglist = ::CommandLineToArgvW(::GetCommandLine(), &nArgc);
if (nArgc && ::GetFileAttributes(szArglist[0]) != INVALID_FILE_ATTRIBUTES) {
// The command line contains the module name.
}
::LocalFree(szArglist);
I hope it can be helpful someone.
Regards, Vladimir
The Problem
I want to press a key when I have a line highlighted and convert from a single line:
JGLogEntry *logEntry = [JGLogEntry applicationNoWindowsFrom:date1 to:date2 intoMOC:mockRawMOC];
to a multiline statement:
JGLogEntry *logEntry = [JGLogEntry applicationNoWindowsFrom:date1
to:date2
intoMOC:mockRawMOC];
What I've Tried
I've got a simple ruby script that almost gets me there.
#!/usr/bin/env ruby
s = STDIN.read
s.gsub!(/(:.+?\w) (\w.+?)/,'\1' + "\n\t" +'\2')
print s
When I set the output to "Replace Selection", I get this:
JGLogEntry *logEntry = [JGLogEntry applicationNoWindowsFrom:date1
to:date2
intoMOC:mockRawMOC];
When I set the output to "Place on Clipboard", then paste it in, I get the desired result:
JGLogEntry *logEntry = [JGLogEntry applicationNoWindowsFrom:date1
to:date2
intoMOC:mockRawMOC];
However, this is two keypresses which is clumsy.
Any ideas how I can get the replaced text to obey Xcode's auto indent rules?
Check the pre-installed script for "Convert tabs to spaces", and how it executes an in-line applescript. Use that to tell XCode to perform the menu item
Edit > Format > Re-Indent
I'm not sure how you do that with ruby, nor the details about the applescript content, but I would wager it's fairly straight-forward..