详解c++中signal信号携带数据的接收与发送

union sigval {
    int   sival_int;
    void *sival_ptr;
};

struct sigaction {
   void     (*sa_handler)(int);       
   void     (*sa_sigaction)(int, siginfo_t *, void *);
   sigset_t   sa_mask;
   int        sa_flags;
   void     (*sa_restorer)(void);
};

#include <iostream>
#include <string>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
 
 
 void DoCmdGetPid(const std::string& cmd, std::string& stringPid)
 {
   FILE *pFile = popen(cmd.c_str(), "r");
   char *buff = new char[256];
   memset(buff, 0, sizeof(buff));
   fread(buff, 1, sizeof(buff), pFile);
   stringPid = buff;
   pclose(pFile);
   delete[] buff;
 }
 
 void SendSig()
 {
   const std::string& procName = "recv";
   std::string cmd = "ps -a | grep " + procName + " |grep -v grep | awk '{print $2}'";
   std::string strPid;
   DoCmdGetPid(cmd, strPid);
 
   if (strPid.empty()) {
       std::cout << "not process\n";
       return;
    }
 
    union sigval sv;
    sv.sival_int = 66;
 
    int res = sigqueue(std::stoi(proc_pid), 38, sv);
    printf("res:%d\n", res);
 
    
   return;
 }
 
 int main()
 {
   while (1) {
     SendSig();
     sleep(5);
   }
 
   return 0;
}

#include <signal.h>
#include <unistd.h>
#include <iostream>
 
void signal_handler(int s, siginfo_t* pSi, void* ucontext)
{
	if (SIGRTMIN + 4 == s) {
		std::cout << "recv sig38\n";
		printf("value:%d\n", pSi->si_value.sival_int);
		printf("value:%d\n", pSi->si_int);
	}
}
 
int main()
{
	struct sigaction act;
	act.sa_sigaction = signal_handler;
	act.sa_flags = SA_SIGINFO;
 
	if (sigaction(SIGRTMIN + 4, &act, nullptr) < 0) {}
 
	while(true) {
		std::cout << "waiting signal..." << std::endl;
		sleep(3);
	}
 
	return 0;
}