stropts.h (0p) - Linux Manuals
stropts.h: STREAMS interface (STREAMS)
NAME
stropts.h - STREAMS interface (STREAMS)
SYNOPSIS
DESCRIPTION
The <stropts.h> header shall define the bandinfo structure that includes at least the following members:
-
unsigned char bi_pri Priority band. int bi_flag Flushing type.
The <stropts.h> header shall define the strpeek structure that includes at least the following members:
-
struct strbuf ctlbuf The control portion of the message. struct strbuf databuf The data portion of the message. t_uscalar_t flags RS_HIPRI or 0.
The <stropts.h> header shall define the strbuf structure that includes at least the following members:
-
int maxlen Maximum buffer length. int len Length of data. char *buf Pointer to buffer.
The <stropts.h> header shall define the strfdinsert structure that includes at least the following members:
-
struct strbuf ctlbuf The control portion of the message. struct strbuf databuf The data portion of the message. t_uscalar_t flags RS_HIPRI or 0. int fildes File descriptor of the other STREAM. int offset Relative location of the stored value.
The <stropts.h> header shall define the strioctl structure that includes at least the following members:
-
int ic_cmd ioctl() command. int ic_timout Timeout for response. int ic_len Length of data. char *ic_dp Pointer to buffer.
The <stropts.h> header shall define the strrecvfd structure that includes at least the following members:
-
int fda Received file descriptor. uid_t uid UID of sender. gid_t gid GID of sender.
The uid_t and gid_t types shall be defined through typedef as described in <sys/types.h> .
The <stropts.h> header shall define the t_scalar_t and t_uscalar_t types, respectively, as signed and unsigned opaque types of equal length of at least 32 bits.
The <stropts.h> header shall define the str_list structure that includes at least the following members:
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int sl_nmods Number of STREAMS module names. struct str_mlist *sl_modlist STREAMS module names.
The <stropts.h> header shall define the str_mlist structure that includes at least the following member:
-
char l_name[FMNAMESZ+1] A STREAMS module name.
At least the following macros shall be defined for use as the request argument to ioctl():
- I_PUSH
- Push a STREAMS module.
- I_POP
- Pop a STREAMS module.
- I_LOOK
- Get the top module name.
- I_FLUSH
- Flush a STREAM.
- I_FLUSHBAND
- Flush one band of a STREAM.
- I_SETSIG
- Ask for notification signals.
- I_GETSIG
- Retrieve current notification signals.
- I_FIND
- Look for a STREAMS module.
- I_PEEK
- Peek at the top message on a STREAM.
- I_SRDOPT
- Set the read mode.
- I_GRDOPT
- Get the read mode.
- I_NREAD
- Size the top message.
- I_FDINSERT
- Send implementation-defined information about another STREAM.
- I_STR
- Send a STREAMS ioctl().
- I_SWROPT
- Set the write mode.
- I_GWROPT
- Get the write mode.
- I_SENDFD
- Pass a file descriptor through a STREAMS pipe.
- I_RECVFD
- Get a file descriptor sent via I_SENDFD.
- I_LIST
- Get all the module names on a STREAM.
- I_ATMARK
- Is the top message "marked''?
- I_CKBAND
- See if any messages exist in a band.
- I_GETBAND
- Get the band of the top message on a STREAM.
- I_CANPUT
- Is a band writable?
- I_SETCLTIME
- Set close time delay.
- I_GETCLTIME
- Get close time delay.
- I_LINK
- Connect two STREAMs.
- I_UNLINK
- Disconnect two STREAMs.
- I_PLINK
- Persistently connect two STREAMs.
- I_PUNLINK
-
Dismantle a persistent STREAMS link.
At least the following macros shall be defined for use with I_LOOK:
- FMNAMESZ
-
The minimum size in bytes of the buffer referred to by the arg
argument.
At least the following macros shall be defined for use with I_FLUSH:
- FLUSHR
- Flush read queues.
- FLUSHW
- Flush write queues.
- FLUSHRW
-
Flush read and write queues.
At least the following macros shall be defined for use with I_SETSIG:
- S_RDNORM
- A normal (priority band set to 0) message has arrived at the head of a STREAM head read queue.
- S_RDBAND
- A message with a non-zero priority band has arrived at the head of a STREAM head read queue.
- S_INPUT
- A message, other than a high-priority message, has arrived at the head of a STREAM head read queue.
- S_HIPRI
- A high-priority message is present on a STREAM head read queue.
- S_OUTPUT
- The write queue for normal data (priority band 0) just below the STREAM head is no longer full. This notifies the process that there is room on the queue for sending (or writing) normal data downstream.
- S_WRNORM
- Equivalent to S_OUTPUT.
- S_WRBAND
- The write queue for a non-zero priority band just below the STREAM head is no longer full.
- S_MSG
- A STREAMS signal message that contains the SIGPOLL signal reaches the front of the STREAM head read queue.
- S_ERROR
- Notification of an error condition reaches the STREAM head.
- S_HANGUP
- Notification of a hangup reaches the STREAM head.
- S_BANDURG
-
When used in conjunction with S_RDBAND, SIGURG is generated instead
of SIGPOLL when a priority message reaches the front of the
STREAM head read queue.
At least the following macros shall be defined for use with I_PEEK:
- RS_HIPRI
-
Only look for high-priority messages.
At least the following macros shall be defined for use with I_SRDOPT:
- RNORM
- Byte-STREAM mode, the default.
- RMSGD
- Message-discard mode.
- RMSGN
- Message-non-discard mode.
- RPROTNORM
- Fail read() with [EBADMSG] if a message containing a control part is at the front of the STREAM head read queue.
- RPROTDAT
- Deliver the control part of a message as data when a process issues a read().
- RPROTDIS
-
Discard the control part of a message, delivering any data part, when
a process issues a read().
At least the following macros shall be defined for use with I_SWOPT:
- SNDZERO
-
Send a zero-length message downstream when a write() of 0 bytes
occurs.
At least the following macros shall be defined for use with I_ATMARK:
- ANYMARK
- Check if the message is marked.
- LASTMARK
-
Check if the message is the last one marked on the queue.
At least the following macros shall be defined for use with I_UNLINK:
- MUXID_ALL
-
Unlink all STREAMs linked to the STREAM associated with fildes.
The following macros shall be defined for getmsg(), getpmsg(), putmsg(), and putpmsg():
- MSG_ANY
- Receive any message.
- MSG_BAND
- Receive message from specified band.
- MSG_HIPRI
- Send/receive high-priority message.
- MORECTL
- More control information is left in message.
- MOREDATA
-
More data is left in message.
The <stropts.h> header may make visible all of the symbols from <unistd.h>.
The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.
-
int isastream(int); int getmsg(int, struct strbuf *restrict, struct strbuf *restrict, int *restrict); int getpmsg(int, struct strbuf *restrict, struct strbuf *restrict, int *restrict, int *restrict); int ioctl(int, int, ... ); int putmsg(int, const struct strbuf *, const struct strbuf *, int); int putpmsg(int, const struct strbuf *, const struct strbuf *, int, int); int fattach(int, const char *); int fdetach(const char *);
The following sections are informative.
APPLICATION USAGE
RATIONALE
FUTURE DIRECTIONS
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
SEE ALSO
<sys/types.h>, <unistd.h>, the System Interfaces volume of IEEE Std 1003.1-2001, close(), fcntl(), getmsg(), ioctl(), open(), pipe(), read(), poll(), putmsg(), signal(), write()