C: Run a System Command and Get Output? [duplicate

问题:

Possible Duplicate:
How can I run an external program from C and parse its output?

I want to run a command in linux and get the text returned of what it outputs, but I do not want this text printed to screen. Is there a more elegant way than making a temporary file?

回答1:

You want the \"popen\" function. Here\'s an example of running the command \"ls /etc\" and outputing to the console.

#include <stdio.h>
#include <stdlib.h>


int main( int argc, char *argv[] )
{

  FILE *fp;
  char path[1035];

  /* Open the command for reading. */
  fp = popen(\"/bin/ls /etc/\", \"r\");
  if (fp == NULL) {
    printf(\"Failed to run command\\n\" );
    exit(1);
  }

  /* Read the output a line at a time - output it. */
  while (fgets(path, sizeof(path)-1, fp) != NULL) {
    printf(\"%s\", path);
  }

  /* close */
  pclose(fp);

  return 0;
}

回答2:

You need some sort of Inter Process Communication. Use a pipe or a shared buffer.

回答3:

Usually, if the command is an external program, you can use the OS to help you here.

command > file_output.txt

So your C code would be doing something like

exec(\"command > file_output.txt\");

Then you can use the file_output.txt file.