C language Get the implementation method of the shell return result _c language

When Linux is programmed, the system method is usually used if we need to invoke a shell command or script. such as System ("LS")

The method returns a value of 0 or-1, that is, success or failure. And sometimes we want to get the result of the shell command execution, what do we do?

We can redirect the shell command results to a file, and then read the file, such as:

System ("Ls>result.txt")

FILE *FP = fopen (result, "R")

Of course, we can also use the pipeline directly, as in the following example:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h >
#include <strings.h>
#include <string.h>

char* shellcmd (char* cmd, char* buff, int size) c7/>{
  Char temp[256];
  file* fp = NULL;
  int offset = 0;
  int Len;
  
  fp = popen (cmd, "R");
  if (fp = = null)
  {return
    null;
  }

  while (fgets (temp, sizeof (temp), FP)!= NULL)
  {
    len = strlen (temp);
    if (offset + len < size)
    {
      strcpy (buff+offset, temp);
      offset = len;
    else
    {
      Buff[offset] = 0;
      break;
    }
  }
  
  if (FP!= NULL)
  {
    pclose (FP);
  }

  return buff;
}

int main (void)
{
  char buff[1024];

  memset (buff, 0, sizeof (buff));
  printf ("%s", Shellcmd ("ls", buff, sizeof (buff));

  return 0;
}

Note: The C language call Shell command is a new process executed, the execution speed is very slow, preferably not C, Shell mixed programming.

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