How to Convert C FILE* to C++ iostream

When we deal with a lot of C libraries in our C++ code, there may be cases where we need to convert the C FILE* into C++ iostream. Boost iostreams can help to deal with such problems easily. Here's an example how to do it.

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#include <iostream> #include <cstdio> #include <unistd.h> #include <boost/iostreams/device/file_descriptor.hpp> #include <boost/iostreams/stream.hpp>   void write() {     FILE* fp = fopen("whatever.txt", "w");     if (fp == NULL) {         perror("fopen error");     }     int fd = fileno(fp);     boost::iostreams::stream_buffer<boost::iostreams::file_descriptor_sink> bis(fd);     std::ostream os(&bis);     os << "Hello World!" << std::endl;       fclose(fp); }   void read() {     FILE* fp = fopen("whatever.txt", "r");     if (fp == NULL) {         perror("fopen error");     }     int fd = fileno(fp);     boost::iostreams::stream_buffer<boost::iostreams::file_descriptor_source> bis(fd);     std::istream is(&bis);     while (is) {         std::string line;         std::getline(is, line);         std::cout << line << std::endl;     }     fclose(fp); }   int main() {     write();     read();       return 0; }