catch2/examples/231-Cfg-OutputStreams.cpp

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// 231-Cfg-OutputStreams.cpp
// Show how to replace the streams with a simple custom made streambuf.
// Note that this reimplementation _does not_ follow `std::cerr`
// semantic, because it buffers the output. For most uses however,
// there is no important difference between having `std::cerr` buffered
// or unbuffered.
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#include <catch2/catch_default_main.hpp>
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#include <catch2/catch_test_macros.hpp>
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#include <sstream>
#include <cstdio>
class out_buff : public std::stringbuf {
std::FILE* m_stream;
public:
out_buff(std::FILE* stream):m_stream(stream) {}
~out_buff();
int sync() override {
int ret = 0;
for (unsigned char c : str()) {
if (putc(c, m_stream) == EOF) {
ret = -1;
break;
}
}
// Reset the buffer to avoid printing it multiple times
str("");
return ret;
}
};
out_buff::~out_buff() { pubsync(); }
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wexit-time-destructors" // static variables in cout/cerr/clog
#endif
namespace Catch {
std::ostream& cout() {
static std::ostream ret(new out_buff(stdout));
return ret;
}
std::ostream& clog() {
static std::ostream ret(new out_buff(stderr));
return ret;
}
std::ostream& cerr() {
return clog();
}
}
TEST_CASE("This binary uses putc to write out output", "[compilation-only]") {
SUCCEED("Nothing to test.");
}