c++ - programming c threaded io -

hi want read text file text , write out file. need threaded 3 party can run @ same time. trying use buffer read in , buffer write out cant work out.

my code :

#include <stdio.h> #include <pthread.h>  char inbuf[1000]; //char outbuf[];  void *readerfun(void *meg){  char *inputfile; file *input_ptr;   inputfile = (char *) meg;  input_ptr = fopen(inputfile, "r");  if(input_ptr == null){     printf("%s\n", inputfile);     printf("input file not working\n");     return; }  while(!feof(input_ptr)){      fscanf(input_ptr, "%s", &inbuf);      sleep(1); //  printf("%s\n", &inbuf ); //  printf("test _____________\n" );    }      return null; }   void *modifierfun(void *meg){  //char c; //while((c = getc(inbuf) != eof)){  //strcat(outbuf, c);  //}  //}   return null; }   void *writerfun(void *meg){  char *outfile; file *output_ptr;  outfile = (char *) meg;  output_ptr = fopen(outfile, "a");  while(inbuf != null){     printf("%s\n", inbuf ); fprintf(output_ptr, "%s", inbuf); }  return null; }   int       main (int argc, char **argv){          pthread_t reader, modifier, writer;         char *meg = argv[1];         char *meg2 = argv[2];         int ret1, ret2, ret3;          ret1 = pthread_create(&reader, null, readerfun, (void *) meg);         ret2 = pthread_create(&modifier, null, modifierfun, (void *) meg);         ret3 = pthread_create(&writer, null, writerfun, (void *) meg2);            pthread_join(reader, null);         pthread_join(modifier, null);         pthread_join(writer, null);          return 0;       } 

would big point me down right road. have looked on net , cant find im looking for.