I'm trying to write a macro that would allow me to do something like: FORMAT(a << "b" << c << d), and the result would be a string -- the same as creating an ostringstream, inserting a...d, and returning .str(). Something like: string f(){ ostringstream o; o << a << "b" << c << d; return o.str() } Essentially, FORMAT(a << "b" ...
Referring to http://stackoverflow.com/questions/303562/c-format-macro-inline-ostringstream The question there was for a macro that allows inline concatenation of objects to create a string, iostream-style. The answer was: #define SSTR( x ) dynamic_cast< std::ostringstream & >( \ ( std::ostringstream().seekp( 0, std::ios_base::...
I'd like to clear out and reuse an ostringstream (and the underlying buffer) so that my app doesn't have to do as many allocations. How do I reset the object to its initial state? ...
I stumbled across this code. std::ostringstream str; /// (some usage) assert( ! str ); What does ostringstream signify when used in a bool context? Is this possibly an incorrect usage that happens to compile and run? ...
I'm testing a Mac OS X port of my multithreaded server. It starts up, but it dies in vsnprintf soon after the first client request is taken by a worker thread. It seems that vsnprintf is trying to manipulate some thread local memory with pthread_setspecific. This dereferences a bad pointer. Then, gdb traps a dlopen call, gets an error,...
I'm trying to create output files subscripted by a dynamic index ( d = {0,...,NUM_DEMES-1}). Currently, I'm only getting output files for the first value (d=0). #include <sstream> #include <string> void Simulation::updateSimulation( double t ) { ... ofstream abundanceStream; ofstream abHeaderStream; if ( step == 1 ) { for ...
Hi all; I've been using the Boost serialization library, which is actually pretty nice, and lets me make simple wrappers to save my serializable objects to strings, like so: template <class T> inline std::string saveString(const T & o) { std::ostringstream oss; boost::archive::binary_oarchive oa(oss); oa << o; return oss.str(); } te...
my_macro << 1 << "hello world" << blah->getValue() << std::endl; should expand into: std::ostringstream oss; oss << 1 << "hello world" << blah->getValue() << std::endl; ThreadSafeLogging(oss.str()); Thanks! EDIT: the accepted answer is awesome. Can we upvote 8 more times and win this responder a badge? (The answer only needs 6 mor...
I came across a subtle bug a couple of days ago where the code looked something like this: ostringstream ss; int anInt( 7 ); ss << anInt << "HABITS"; ss << ends; string theWholeLot = ss.str(); The problem was that the ends was sticking a '\0' into the ostringstream so theWholeLot actually looked like "7HABITS\0" (i.e. a null at the e...
I am writing an embedded app. In some places, I use std::ostringstream a lot, since it is very convenient for my purposes. However, I just discovered that the performance hit is extreme since adding data to the stream results in a lot of calls to malloc and free. Is there any way to avoid it? My first thought was making the ostringstrea...
std::ostringstream parmStream; char parmName[1024]; THTTPUrl::Encode(parmName, pParm->Name().c_str(), 1024); //I want to add the value of the paramName to the parmStream worked b4 when parmName was a string but obv not now parmStream << "&" << parmName + "="; Gives me the following .. error: invalid operands of types \u2018char ...
Hi, I want to derive a stringstream so that I can use the operator<< to construct a message which will then be thrown. The API would look like: error("some text") << " more text " << 42 << std::endl; This should do a throw "some text more text 42" So what I did is make an errorbuf (inheriting from streambuf) which overloads the 'ov...
In C++ I need string representations of integers with leading zeroes, where the representation has 8 digits and no more than 8 digits, truncating digits on the right side if necessary. I thought I could do this using just ostringstream and iomanip.setw(), like this: int num_1 = 3000; ostringstream out_target; out_target << setw(8) << ...
Hi all, I have come across a situation (on Win32) where the std::ostringstream object continues to consume process memory, even when it is ostensibly cleared out after a series of append-type operations. Please take a look at this C++ fragment: int main(void) { std::ostringstream cOutputLogStream; // Random long string std...
Hello, I think the title says pretty much everything, hehe. I would like you to tell me when to use std::istringstream, std::ostringstream and std::stringstream and why I shouldn't just use std::stringstream in every scenario (like are there any runtime performance issues?). Thanks! PS: I have a third, less important question. Is ther...
Hi, I have an issue regarding conversion from float to c++ string using ostringstream. Here is my line: void doSomething(float t) { ostringstream stream; stream << t; cout << stream.str(); } when t has value -0.89999 it is round off to -0.9, but when it's value is 0.0999 or lesser than this say 1.754e-7, it just prints w...
Hi, in C++ (on Linux with gcc) I'd like to put a byte array (vector<unsigned char>) to a ostringstream or a string. I know that I can use sprintf but it doesn't seem to be the best way to use char* also. btw: this link did not help Edit: All answer work so far. But I did not meantion, that I'd like to convert the bytes/hex-values int...
On MSVC 2005, I have the following code. std::ostringstream stream("initial string "); stream << 5; std::cout << stream.str(); What I expect is: initial string 5 What I get is: 5nitial string Initializing the stream with a string, I would expect the stream to move its position to the end of the initial string. Obviously, STL doe...