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scrappyscrappy
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Newer version of Bruce's pginterface library...
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‎contrib/pginterface/Makefile

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#
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# Makefile
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#
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#
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PGINTERFACE = pginterface.o halt.o
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TARGET = pginsert pgwordcount pgnulltest
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CFLAGS = -g -Wall -I/u/postgres95/include
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LDFLAGS = -L/u/postgres95/lib -lpq
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all : $(TARGET)
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$(TARGET): $(PGINTERFACE) $*.c
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cc -o $* $(CFLAGS) $*.c $(PGINTERFACE) $(LDFLAGS)
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$(PGINTERFACE): pginterface.c halt.c
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cc -c $(CFLAGS) pginterface.c halt.c
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clean:
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rm -f *.o $(TARGET) log core
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install:
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make clean
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make CFLAGS=-O
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install -s -o bin -g bin $(TARGET) /usr/local/bin

‎contrib/pginterface/README

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Pginterface 1.0
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Attached is a copy of the Postgres support routines I wrote to allow me
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to more cleanly interface to the libpg library, more like a 4gl SQL
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interface.
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It has several features that may be useful for others:
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I have simplified the C code that calls libpq by wrapping all the
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functionality of libpq in calls to connectdb(), doquery(), fetch(),
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fetchisnull() and disconnectdb(). Each call returns a structure or
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value, so if you need to do more work with the result, you can. Also, I
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have a global variable that allows you to disable the error checking I
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have added to the doquery() routine.
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I have added a function called fetch(), which allows you to pass
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pointers as parameters, and on return the variables are filled with the
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data from the binary cursor you opened. These binary cursors are not
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useful if you are running the query engine on a system with a different
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architecture than the database server. If you pass a NULL pointer, the
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column is skipped, and you can use libpq to handle it as you wish.
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I have used sigprocmask() to block the reception of certain signals
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while the program is executing SQL queries. This prevents a user
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pressing Control-C from stopping all the back ends. It blocks SIGHUP,
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SIGINT, and SIGTERM, but does not block SIGQUIT or obviously kill -9.
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If your platform does not support sigprocmask(), you can remove those
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function calls. ( Am I correct that abnormal termination can cause
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shared memory resynchronization?)
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There is a demo program called pginsert that demonstrates how the
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library can be used.
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You can create a library of pginterface.c and halt.c, and just include
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pginterface.h in your source code.
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I am willing to maintain this if people find problems or want additional
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functionality.
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Bruce Momjian (root@candle.pha.pa.us)

‎contrib/pginterface/halt.c

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/*
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**
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** halt.c
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**
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** This is used to print out error messages and exit
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*/
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#include <varargs.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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/*-------------------------------------------------------------------------
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**
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** halt - print error message, and call clean up routine or exit
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**
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**------------------------------------------------------------------------*/
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/*VARARGS*/
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void halt(va_alist)
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va_dcl
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{
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va_list arg_ptr;
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char *format, *pstr;
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void (*sig_func)();
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va_start(arg_ptr);
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format = va_arg(arg_ptr,char *);
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if (strncmp(format,"PERROR", 6) != 0)
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vfprintf(stderr,format,arg_ptr);
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else
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{
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for (pstr=format+6; *pstr == ' ' || *pstr == ':'; pstr++)
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;
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vfprintf(stderr,pstr,arg_ptr);
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perror("");
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}
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va_end(arg_ptr);
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fflush(stderr);
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/* call one clean up function if defined */
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if ( (sig_func = signal(SIGTERM, SIG_DFL)) != SIG_DFL &&
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sig_func != SIG_IGN)
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(*sig_func)(0);
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else if ( (sig_func = signal(SIGHUP, SIG_DFL)) != SIG_DFL &&
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sig_func != SIG_IGN)
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(*sig_func)(0);
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else if ( (sig_func = signal(SIGINT, SIG_DFL)) != SIG_DFL &&
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sig_func != SIG_IGN)
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(*sig_func)(0);
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else if ( (sig_func = signal(SIGQUIT, SIG_DFL)) != SIG_DFL &&
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sig_func != SIG_IGN)
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(*sig_func)(0);
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exit(1);
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}

‎contrib/pginterface/halt.h

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/*
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** halt.h
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**
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*/
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void halt();
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‎contrib/pginterface/pginsert.c

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/*
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* insert.c
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*
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*/
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#include <stdio.h>
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#include <signal.h>
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#include <time.h>
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#include <libpq-fe.h>
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#include "halt.h"
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#include "pginterface.h"
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int main(int argc, char **argv)
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{
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char query[4000];
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int row =1;
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int aint;
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float afloat;
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double adouble;
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char achar[11], achar16[17], abpchar[11], avarchar[51], atext[51];
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time_t aabstime;
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if (argc != 2)
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halt("Usage: %s database\n",argv[0]);
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connectdb(argv[1],NULL,NULL,NULL,NULL);
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on_error_continue();
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doquery("DROP TABLE testfetch");
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on_error_stop();
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doquery("\
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CREATE TABLE testfetch( \
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aint int4, \
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afloat float4, \
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adouble float8, \
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achar char, \
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achar16 char16, \
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abpchar char(10), \
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avarchar varchar(50), \
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atext text, \
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aabstime abstime) \
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");
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while(1)
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{
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sprintf(query,"INSERT INTO testfetch VALUES ( \
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%d, \
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2322.12, \
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'923121.0323'::float8, \
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'A', \
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'Betty', \
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'Charley', \
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'Doug', \
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'Ernie', \
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'now' )", row);
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doquery(query);
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doquery("BEGIN WORK");
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doquery("DECLARE c_testfetch BINARY CURSOR FOR \
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SELECT * FROM testfetch");
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doquery("FETCH ALL IN c_testfetch");
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while (fetch(
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&aint,
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&afloat,
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&adouble,
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achar,
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achar16,
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abpchar,
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avarchar,
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atext,
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&aabstime) != END_OF_TUPLES)
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printf("int %d\nfloat %f\ndouble %f\nchar %s\nchar16 %s\n\
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bpchar %s\nvarchar %s\ntext %s\nabstime %s",
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aint,
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afloat,
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adouble,
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achar,
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achar16,
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abpchar,
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avarchar,
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atext,
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ctime(&aabstime));
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doquery("CLOSE c_testfetch");
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doquery("COMMIT WORK");
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printf("--- %-d rows inserted so far\n",row);
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row++;
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}
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disconnectdb();
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return 0;
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}
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