refactor(pipe): attach error code to exceptions via std::system_error

Author: mikucionisaau

source/matplot/util/common.cpp

@@ -50,11 +50,18 @@ namespace matplot {
  iequals(str, "no");
  }
 
+ struct pipe_deleter {
+ int operator()(FILE* pipe) const {
+ if (int status = PCLOSE(pipe); status != -1)
+ return status;
+ throw std::system_error{errno, std::system_category(), "pclose"};
+ }
+ };
+
  std::string run_and_get_output(const std::string &cmd) {
- std::unique_ptr<FILE, int (*)(FILE *)> pipe(POPEN(cmd.c_str(), "r"),
- PCLOSE);
+ std::unique_ptr<FILE, pipe_deleter> pipe(POPEN(cmd.c_str(), "r"));
  if (!pipe) {
- throw std::runtime_error("popen() failed!");
+ throw std::system_error{errno, std::system_category(), cmd};
  }
  std::array<char, 128> buffer{};
  std::string result;
@@ -363,7 +370,7 @@ namespace matplot {
  std::string fileread(const std::string &filename) {
  std::ifstream t(filename);
  if (!t) {
- throw std::runtime_error("Cannot open the file " + filename);
+ throw std::system_error(errno, std::system_category(), filename);
  }
  std::string str((std::istreambuf_iterator<char>(t)),
  std::istreambuf_iterator<char>());