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/*------------------------------------------------------------------------
*
* This simple client program starts up an imview, where the portfile
* is in fact a named pipe. This is trickier than with a file but it
* works better if you want to start several imviews, as it forces
* a measure of synchronization.
*
* Hugues Talbot 14 Mar 2001
*
*-----------------------------------------------------------------------*/
#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#define PROG "startim"
#define PIPESTR "/tmp/toto"
#define IMVIEWCMD "imview -server -fork -portfile " PIPESTR
#define FAIL do {perror(PROG); unlink(PIPESTR); exit(1);} while (0)
int main()
{
char *execstring = IMVIEWCMD;
char buffer[5];
int portnum, filenum, res;
unlink(PIPESTR); /* might fail, don't care */
res = mkfifo(PIPESTR,S_IRUSR|S_IWUSR);
if (res != 0)
FAIL;
/* open the pipe for reading, notice the NO DELAY */
filenum = open(PIPESTR, O_RDONLY | O_NDELAY, 0);
if (filenum < 0)
FAIL;
/* then exec imview */
printf("Imview away...\n");
system(execstring);
/* then read the pipe */
memset(buffer, '\0', 5);
if (read(filenum, buffer, 4) <= 0)
FAIL;
printf("port number is %s\n", buffer);
close(filenum);
unlink(PIPESTR);
return 0;
}
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