get the process path by PID on macOS. example: make pathfind && ./pathfind 86504

pathfind.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <libproc.h>

int main(int argc, char* argv[])
{
    pid_t pid;
    int ret;
    char pathbuf[PROC_PIDPATHINFO_MAXSIZE];

    for (int i = 1; i < argc; ++i)
    {
        pid = (pid_t) atoi(argv[i]);
        ret = proc_pidpath(pid, pathbuf, sizeof(pathbuf));
        if (ret <= 0)
	{
            fprintf(stderr, "pid %d: proc_pidpath error: %s\n", pid, strerror(errno));
        }
	else
	{
            printf("pid %d: %s\n", pid, pathbuf);
        }
    }

    return 0;
}