How to overwrite only part of a file in c++
I want to make modifications to the middle of a text file using c++, without altering the rest of the file. How can I do that? ...
g++
Is modifying a file without writing a new file possible in c++?
Let's say I have a text file that is 100 lines long. I want to only change what is in the 50th line. One way to do it is open the file for input and open a new file for output. Use a for-loop to read in the first half of the file line by line and write to the second file line by line, then write what I want to change, and then write o...
How to read in space-delimited information from a file in c++
In a text file I will have a line containing a series of numbers, with each number separated by a space. How would I read each of these numbers and store all of them in an array? ...
Different ways to specify libraries to gcc/g++
I'd be curious to understand if there's any substantial difference in specifying libraries (both shared and static) to gcc/g++ in the two following ways (CC can be g++ or gcc) CC -o output_executable /path/to/my/libstatic.a /path/to/my/libshared.so source1.cpp source2.cpp ... sourceN.cpp vs CC -o output_executable -L/path/to/my/libs ...
Eclipse CDT: cannot debug or terminate application
I have Eclipse set up fairly nicely to run the G++ compiler through Cygwin. Even the character encoding is set up correctly! There still seems to be something wrong with my configuration: I can't debug. The pause button in the debug view is simply disabled, and no threads appear in my application tree. It seems that gdb is simply not co...
[GCC, linking] How to link app with static library + why this is not working
I have a problem. I wrote example code and I want to build it without the error: main.cpp(.text+0x5): undefined reference to `test()' Library test1.c #include <stdlib.h> void test() { puts("Działa"); } test1.h #ifndef TEST1_H #define TEST1_H extern void test(); #endif makefile all: gcc -c ./src/test1.c -o ./lib/test1.o ...
C++ list<T>::iterator cant be used in derived class template
g++ compiler gives this error: expected `;' before 'it' template <typename T> class myList : public std::list<T> { public: void foo () { std::list<T>::iterator it; // compiler error as above mentioned, why ??? } }; Thanks. ...
c++ g++ llvm-clang compiler profiling
Note, my question is not: how do I tell my compiler to compile with profiling on. I want to profile my compiles process. For each file, I'd like to know how much time is spent on each line of the program. I'm working on a project, some files have huge compile times, I'm trying to figure out why. Is there anyway to do this with g++ or ...
Is there any g++ option to dump class layout and vtables?
Hi I want to see how g++ lays out memory for classes and virtual tables. Is there a way to dump this information, using g++'s options? Thanks ...
"call" instruction that seemingly jumps into itself
I have some C++ code #include <cstdio> #include <boost/bind.hpp> #include <boost/function.hpp> class A { public: void do_it() { std::printf("aaa"); } }; void call_it(const boost::function<void()> &f) { f(); } void func() { A *a = new A; call_it(boost::bind(&A::do_it, a)); } which gcc 4 compiles into the following as...
Singleton code linker errors in vc 9.0. Runs fine in linux compiled with gcc
I have a simple logger that is implemented as a singleton. It works like i want when I compile and run it with g++ in linux but when I compile in Visual Studio 9.0 with vc++ I get the following errors. Is there a way to fix this? I don't mind changing the logger class around, but I would like to avoid changing how it is called. 1>Linkin...
Actual long double precision does not agree with std::numeric_limits
Working on Mac OS X 10.6.2, Intel, with i686-apple-darwin10-g++-4.2.1, and compiling with the -arch x86_64 flag, I just noticed that while... std::numeric_limits<long double>::max_exponent10 = 4932 ...as is expected, when a long double is actually set to a value with exponent greater than 308, it becomes inf--ie in reality it only has...
Linker error when compiling boost.asio example
Hi, I'm trying to learn a little bit C++ and Boost.Asio. I'm trying to compile the following code example: #include <iostream> #include <boost/array.hpp> #include <boost/asio.hpp> using boost::asio::ip::tcp; int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr << "Usage: client <host>" << std::endl; ...
Enabling <> for headers in g++
I'm having an issue getting some code to work. Is there a way to enable headers to be included like so #include <boost/asio.hpp> Instead of #include "boost/asio.hpp" ...
g++/clang ultra fast parse but not compile mode?
Is there some ultra fast "syntax check my code, but don't compile mode" for g++/clang? Where the only goal is to just check if the code I have is valid C++ code? ...
How to change this C++ code to make input work better
cout << "Input street number: "; cin >> streetnum; cout << "Input street name: "; cin >> streetname; cout << "Input resource name: "; cin >> rName; cout << "Input architectural style: "; cin >> aStyle; cout << "Input year built: "; cin >> year; The problem ...
Testing C++ program with Testing classes over normally used classes
Hi Guys, This will probably be a bot of a waffly question but ill try my best. I have a simple c++ program that i need to build testing for. I have 2 Classes i use besides the one i actually am using, these are called WebServer and BusinessLogicLayer. To test my own code i have made my own versions of these classes that feed dummy da...
invalid conversion from ‘char*’ to ‘char’
Hi Guys, I have a, int main (int argc, char *argv[]) and one of the arguements im passing in is a char. It gives the error message in the title when i go to compile How would i go about fixing this? Regards Paul ...
Using Valgrind tool how can I detect which object trying to access 0x0 address ?
I have this output when trying to debug Program received signal SIGSEGV, Segmentation fault 0x43989029 in std::string::compare (this=0x88fd430, __str=@0xbfff9060) at /home/devsw/tmp/objdir/i686-pc-linux-gnu/libstdc++-v3/include/bits/char_traits.h:253 253 { return memcmp(__s1, __s2, __n); } Current language: auto; currently ...
Using Library files in Linux
Hi Guys, Im trying to use some of the functions that are in the /lib/libproc-3.2.6.so library in my Ubuntu Distribution. I have downloaded and installed the header files and they are defined in my source files. Currently this is all im trying to do, just for starters... proc_t **read_proc = readproctab(0); But i get the following...