text: /*
   * MIT License
   *
   * Copyright (c) 2021 Ozan Tezcan
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #ifndef SC_SIGNAL_H
  #define SC_SIGNAL_H
  
  #include <signal.h>
  #include <stddef.h>
  #include <stdarg.h>
  
  #define SC_SIGNAL_VERSION "1.0.0"
  
  /**
   * Set shutdown fd here. When shutdown signal is received e.g SIGINT, SIGTERM.
   * Signal handler will write 1 byte to shutdown fd. So, your app can detect
   * shutdown command received and shutdown properly (Assuming you observe this fd
   * with select() like function). Before app shutdowns, if another shutdown
   * signal is received, _Exit() is called without waiting.
   * e.g CTRL+C to shutdown, twice CTRL+C means 'I don't want to wait anything'.
   */
  #if defined(_WIN32)
      #include <WinSock2.h>
      extern volatile SOCKET sc_signal_shutdown_fd;
  #else
      extern volatile sig_atomic_t sc_signal_shutdown_fd;
  #endif
  
  /**
   * Set log file fd here, logging will be redirected to this fd, otherwise
   * STDERR_FILENO or STDOUT_FILENO will be used.
   */
  extern volatile sig_atomic_t sc_signal_log_fd;
  
  
  // Internal variable to handle twice shutdown signal.
  extern volatile sig_atomic_t sc_signal_will_shutdown;
  
  /**
   * Init signal handler, hooks for shutdown signals and some fatal signals.
   * @return '0' on success, '-1' on failure
   */
  int sc_signal_init();
  
  /**
   * Signal safe logging
   *
   * @param fd   fd to write log
   * @param buf  buf
   * @param size size
   * @param fmt  fmt
   * @param ...  args
   */
  void sc_signal_log(int fd, char *buf, size_t size, char *fmt, ...);
  
  /**
   * Signal safe vsnprintf.
   * Supports only "%s, "%u", "%lu", "%llu", "%d", "%ld", "%lld" and "%p"
   *
   * @param buf  buf
   * @param size size
   * @param fmt  fmt
   * @param va   va_list
   * @return     number of characters written on success, '-1' on failure.
   */
  int sc_signal_vsnprintf(char *buf, size_t size, const char *fmt, va_list va);
  
  /**
   * Signal safe snprintf.
   * Supports only "%s, "%u", "%lu", "%llu", "%d", "%ld", "%lld" and "%p"
   *
   * @param buf  buf
   * @param size size
   * @param fmt  fmt
   * @param ...  args
   * @return     number of characters written on success, '-1' on failure.
   */
  int sc_signal_snprintf(char *buf, size_t size, const char *fmt, ...);
  
  #endif
  