PSPDET - Simple Proper Detacher

pspdet.c

//pspdet: PSPDET Simple Proper Detacher
//References: 
// - http://stackoverflow.com/a/8888612
// - Unix Network programming 3rd Ed., Vol. 1 

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>

#define unlikely(x)  __builtin_expect(!!(x), 0)

#define MACRO_WRAP(x) do { x } while(0)
#define TRY(expr, tst) MACRO_WRAP( \
if( unlikely( !((expr) tst) ) ) { \
  if(errno != 0) { \
    perror("" # expr); \
    exit(errno); \
  } else { \
    puts("Unknown error" # expr); \
    exit(-1); \
  } \
} )


int main(int argc, char** argv) {

  if(argc < 2)
    return 1;

  TRY(daemon(1, 0), != -1);

  TRY(signal(SIGHUP, SIG_IGN), != SIG_IGN);

  pid_t p;
  TRY(p = fork(), != -1);

  if(p == 0)
    TRY(execvp(argv[1], argv+1), == -1);

}