From 78e51a8c6678b6e3dff3d619aa786669f531f4bc Mon Sep 17 00:00:00 2001 From: rsc Date: Fri, 14 Jan 2005 03:45:44 +0000 Subject: checkpoint --- man/man3/ioproc.html | 211 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 211 insertions(+) create mode 100644 man/man3/ioproc.html (limited to 'man/man3/ioproc.html') diff --git a/man/man3/ioproc.html b/man/man3/ioproc.html new file mode 100644 index 00000000..092bac91 --- /dev/null +++ b/man/man3/ioproc.html @@ -0,0 +1,211 @@ + +ioproc(3) - Plan 9 from User Space + + + + +
+
+
IOPROC(3)IOPROC(3) +
+
+

NAME
+ +
+ + closeioproc, iocall, ioclose, iointerrupt, iodial, ioopen, ioproc, + ioread, ioread9pmsg, ioreadn, iorecvfd, iosendfd, iosleep, iowrite + – slave I/O processes for threaded programs
+ +
+

SYNOPSIS
+ +
+ + +
+ + #include <u.h>
+ #include <libc.h>
+ #include <thread.h>
+ typedef struct Ioproc Ioproc;
+ Ioproc* ioproc(void);
+ int       ioclose(Ioproc *io, int fd);
+ int       iodial(Ioproc *io, char *addr, char *local, char *dir, char + *cdfp);
+ int       ioopen(Ioproc *io, char *file, int omode);
+ long      ioread(Ioproc *io, int fd, void *a, long n);
+ int       ioread9pmsg(Ioproc *io, int fd, void *a, uint n);
+ long      ioreadn(Ioproc *io, int fd, void *a, long n);
+ int       iorecvfd(int socket);
+ int       iosendfd(int socket, int fd);
+ int       iosleep(int milli);
+ long      iowrite(Ioproc *io, int fd, void *a, long n);
+ void      iointerrupt(Ioproc *io);
+ void      closeioproc(Ioproc *io);
+ long      iocall(Ioproc *io, long (*op)(va_list *arg), ...);
+ +
+

DESCRIPTION
+ +
+ + +
+ + These routines provide access to I/O in slave procs. Since the + I/O itself is done in a slave proc, other threads in the calling + proc can run while the calling thread waits for the I/O to complete. + +
+ + Ioproc forks a new slave proc and returns a pointer to the Ioproc + associated with it. Ioproc uses mallocz and proccreate; if either + fails, it calls sysfatal rather than return an error. +
+ + Ioclose, iodial, ioopen, ioread, ioread9pmsg, ioreadn, iorecvfd, + iosendfd, iosleep, and iowrite execute the similarly named library + or system calls (see close(2), dial(3), open(3), read(3), fcall(3), + sendfd(3), and sleep(3)) in the slave process associated with + io. It is an error to execute more than one call at a time in + an I/O + proc. +
+ + Iointerrupt interrupts the call currently executing in the I/O + proc. If no call is executing, iointerrupt is a no-op. +
+ + Closeioproc terminates the I/O proc and frees the associated Ioproc + . +
+ + Iocall is a primitive that may be used to implement more slave + I/O routines. Iocall arranges for op to be called in io’s proc, + with arg set to the variable parameter list, returning the value + that op returns.
+ +
+

EXAMPLE
+ +
+ + Relay messages between two file descriptors, counting the total + number of bytes seen:
+ +
+ + int tot;
+ void
+ relaythread(void *v)
+ {
+ +
+ + int *fd, n;
+ char buf[1024];
+ Ioproc *io;
+ fd = v;
+ io = ioproc();
+ while((n = ioread(io, fd[0], buf, sizeof buf)) > 0){
+ if(iowrite(io, fd[1], buf, n) != n)
+ sysfatal("iowrite: %r");
+ tot += n;
+ }
+ closeioproc(io);
+ +
+ }
+ void
+ relay(int fd0, int fd1)
+ {
+ +
+ + int fd[4];
+ fd[0] = fd[3] = fd0;
+ fd[1] = fd[2] = fd1;
+ threadcreate(relaythread, fd, 8192);
+ threadcreate(relaythread, fd+2, 8192);
+ +
+ }
+ +
+ + +
+ If the two relaythread instances were running in different procs, + the common access to tot would be unsafe. +
+ + Implement ioread:
+ +
+ + static long
+ _ioread(va_list *arg)
+ {
+ +
+ + int fd;
+ void *a;
+ long n;
+ fd = va_arg(*arg, int);
+ a = va_arg(*arg, void*);
+ n = va_arg(*arg, long);
+ return read(fd, a, n);
+ +
+ }
+ long
+ ioread(Ioproc *io, int fd, void *a, long n)
+ {
+ +
+ + return iocall(io, _ioread, fd, a, n);
+ +
+ }
+ +
+ +
+

SOURCE
+ +
+ + /usr/local/plan9/src/libthread
+ +
+

SEE ALSO
+ +
+ + dial(3), open(3), read(3), thread(3)
+ +
+

BUGS
+ +
+ + Iointerrupt is currently unimplemented.
+ +
+ +

 +
+
+ + +
+
+
+Space Glenda +
+
+ + -- cgit v1.2.3