Capturing stdout from a system() command optimally [duplicate]

I'm trying to start an external application through system() - for example, system("ls"). I would like to capture its output as it happens so I can send it to another function for further processing. What's the best way to do that in C/C++?

Solution 1:

From the popen manual:

#include <stdio.h>

FILE *popen(const char *command, const char *type);

int pclose(FILE *stream);

Solution 2:

Try the popen() function. It executes a command, like system(), but directs the output into a new file. A pointer to the stream is returned.

  FILE *lsofFile_p = popen("lsof", "r");

  if (!lsofFile_p)
  {
    return -1;
  }

  char buffer[1024];
  char *line_p = fgets(buffer, sizeof(buffer), lsofFile_p);
  pclose(lsofFile_p);