p2close man page on SmartOS

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P2OPEN(3GEN)							  P2OPEN(3GEN)

NAME
       p2open, p2close - open, close pipes to and from a command

SYNOPSIS
       cc [ flag ... ] file ... -lgen [ library ... ]
       #include <libgen.h>

       int p2open(const char *cmd, FILE *fp[2]);

       int p2close(FILE *fp[2]);

DESCRIPTION
       The  p2open()gfunction forks and execs a shell running the command line
       pointed to by cmd. On return, fp[0] points to a FILE pointer  to	 write
       the command's standard input and fp[1] points to a FILE pointer to read
       from the command's  standard output.  In this way the program has  con‐
       trol over the input and output of the command.

       The function returns 0 if successful; otherwise, it returns −1.

       The p2close() function is used to close the file pointers that p2open()
       opened.	It waits for the process to terminate and returns the  process
       status. It returns 0 if successful; otherwise, it returns −1.

RETURN VALUES
       A  common  problem  is  having  too few file descriptors. The p2close()
       function returns −1 if the two file pointers  are  not  from  the  same
       p2open().

EXAMPLES
       Example 1 Example of file descriptors.

	 #include <stdio.h>
	 #include <libgen.h>

	 main(argc,argv)
	 int argc;
	 char **argv;
	 {
	      FILE *fp[2];
	      pid_t pid;
	      char buf[16];

		 pid=p2open("/usr/bin/cat", fp);
		 if ( pid == −1 ) {
		   fprintf(stderr, "p2open failed\n");
		   exit(1);
	      }
	      write(fileno(fp[0]),"This is a test\n", 16);
	      if(read(fileno(fp[1]), buf, 16) <=0)
		   fprintf(stderr, "p2open failed\n");
	      else
		   write(1, buf, 16);
	      (void)p2close(fp);
	 }

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

       ┌───────────────┬─────────────────┐
       │ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
       ├───────────────┼─────────────────┤
       │MT-Level       │ Unsafe		 │
       └───────────────┴─────────────────┘

SEE ALSO
       fclose(3C), popen(3C), setbuf(3C), attributes(5)

NOTES
       Buffered	 writes	 on  fp[0]  can make it appear that the command is not
       listening. Judiciously placed fflush() calls or unbuffering  fp[0]  can
       be a big help; see fclose(3C).

       Many  commands use buffered output when connected to a pipe. That, too,
       can make it appear as if things are not working.

       Usage is not the same as for popen(), although it is closely related.

				 Dec 29, 1996			  P2OPEN(3GEN)
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