popen function

popen is used to read and write to a unix pipe.

This function is NOT included in 'C Programming Language' (ANSI) but can be found in 'The Standard C Library' book.

Library:   stdio.h

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

Syntax:    FILE *fp;
	   fp = popen( "ls -l", "r");

Notes:
	command - is the command to be issued.
	type    - r - read O/P from command.
                - w - Write data as I/P to command.

Examples:

Notes:

• popen will always execute the command from within the Bourne shell.
• popen feeds the STDOUT back to your program. If you want STDERR, the following will do the trick.

  	fp=popen("ls -l 2>&1", "w");
  		        AAAA
  		        ||||
  

See Also:

• fgetc Get a character from a file.
• fputc Put a character into a file.man pages
• fprintf Put a formatted line into a file.
• fopen Open a file.
• fclose Close a file.
• pclose Close a pipe.
• system Open a pipe.