p2close(3gen) [sunos man page]

p2open(3GEN)					     String Pattern-Matching Library Functions					      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

       p2open()  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 com-
       mand'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 control over the input and output of the command.

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

       p2close() 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. p2close() 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
");
		 exit(1);
	    }
	    write(fileno(fp[0]),"This is a test
", 16);
	    if(read(fileno(fp[1]), buf, 16) <=0)
		 fprintf(stderr, "p2open failed
");
	    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.

SunOS 5.10							    29 Dec 1996 						      p2open(3GEN)

p2open(3GEN)					     String Pattern-Matching Library Functions					      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

       p2open()  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 com-
       mand'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 control over the input and output of the command.

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

       p2close() 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. p2close() 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
");
		 exit(1);
	    }
	    write(fileno(fp[0]),"This is a test
", 16);
	    if(read(fileno(fp[1]), buf, 16) <=0)
		 fprintf(stderr, "p2open failed
");
	    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.

SunOS 5.10							    29 Dec 1996 						      p2open(3GEN)