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Add PQunescapeBytea libpq function.
Everyone using libpq and bytea is probably having to invent this wheel.. Patrick Welche
This commit is contained in:
Bruce Momjian
parent
b2aade0e4b
commit
294f0d4bd6
@ -1,5 +1,5 @@
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<!--
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$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.87 2002/01/18 20:39:04 momjian Exp $
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$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.88 2002/03/04 23:59:11 momjian Exp $
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-->
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<chapter id="libpq">
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@ -955,6 +955,25 @@ strings overlap.
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byte is also added. The single quotes that must surround
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PostgreSQL string literals are not part of the result string.
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</para>
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<para>
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<function>PQunescapeBytea</function>
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Converts an escaped string representation of binary data into binary
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data - the reverse of <function>PQescapeBytea</function>.
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<synopsis>
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unsigned char *PQunescapeBytea(unsigned char *from, size_t *to_length);
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</synopsis>
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The <paramater>from</parameter> parameter points to an escaped string
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such as might be returned by <function>PQgetvalue</function> of a
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<type>BYTEA</type> column. <function>PQunescapeBytea</function> converts
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this NUL terminated string representation into binary, filling a buffer.
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It returns a pointer to the buffer which is NULL on error, and the size
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of the buffer in <parameter>to_length</parameter>. The pointer may
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subsequently be used as an argument to the function
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<function>free(3)</function>.
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</para>
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</sect2>
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: elog.h,v 1.32 2002/03/04 01:46:04 tgl Exp $
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* $Id: elog.h,v 1.33 2002/03/04 23:59:14 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -15,27 +15,28 @@
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#define ELOG_H
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/* Error level codes */
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#define DEBUG5 10 /* Debugging messages, in categories
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* of decreasing detail. */
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#define DEBUG4 11
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#define DEBUG3 12
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#define DEBUG2 13
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#define DEBUG1 14
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#define LOG 15 /* Server operational history messages;
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* sent only to server log by default. */
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#define COMMERROR 16 /* Client communication problems; same as
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* LOG for server reporting, but never ever
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* try to send to client. */
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#define INFO 17 /* Informative messages that are part of
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* normal query operation; sent only to
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* client by default. */
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#define NOTICE 18 /* Important messages, for unusual cases that
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* should be reported but are not serious
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* enough to abort the query. Sent to client
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* and server log by default. */
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#define ERROR 19 /* user error - return to known state */
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#define FATAL 20 /* fatal error - abort process */
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#define PANIC 21 /* take down the other backends with me */
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#define DEBUG5 10 /* Debugging messages, in categories
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* of decreasing detail. */
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#define DEBUG4 11
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#define DEBUG3 12
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#define DEBUG2 13
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#define DEBUG1 14
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#define LOG 15 /* Server operational history messages;
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* sent only to server log by default. */
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#define COMMERROR 16 /* Client communication problems; same as
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* LOG for server reporting, but never ever
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* try to send to client. */
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#define INFO 17 /* Informative messages that are part of
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* normal query operation; sent only to
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* client by default. */
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#define INFOALWAYS 18 /* Like INFO, but always prints to client */
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#define NOTICE 19 /* Important messages, for unusual cases that
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* should be reported but are not serious
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* enough to abort the query. Sent to client
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* and server log by default. */
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#define ERROR 20 /* user error - return to known state */
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#define FATAL 21 /* fatal error - abort process */
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#define PANIC 22 /* take down the other backends with me */
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/*#define DEBUG DEBUG1*/ /* Backward compatibility with pre-7.3 */
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.113 2001/10/25 05:50:13 momjian Exp $
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* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-exec.c,v 1.114 2002/03/04 23:59:14 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -180,6 +180,95 @@ PQescapeBytea(unsigned char *bintext, size_t binlen, size_t *bytealen)
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return result;
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}
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/*
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* PQunescapeBytea - converts the null terminated string representation
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* of a bytea, strtext, into binary, filling a buffer. It returns a
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* pointer to the buffer which is NULL on error, and the size of the
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* buffer in retbuflen. The pointer may subsequently be used as an
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* argument to the function free(3). It is the reverse of PQescapeBytea.
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*
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* The following transformations are reversed:
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* '\0' == ASCII 0 == \000
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* '\'' == ASCII 39 == \'
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* '\\' == ASCII 92 == \\
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*
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* States:
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* 0 normal 0->1->2->3->4
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* 1 \ 1->5
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* 2 \0 1->6
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* 3 \00
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* 4 \000
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* 5 \'
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* 6 \\
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*/
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unsigned char *
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PQunescapeBytea(unsigned char *strtext, size_t *retbuflen)
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{
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size_t buflen;
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unsigned char *buffer, *sp, *bp;
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unsigned int state=0;
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if(strtext == NULL)return NULL;
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buflen = strlen(strtext); /* will shrink, also we discover if strtext */
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buffer = (unsigned char *) malloc(buflen); /* isn't NULL terminated */
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if(buffer == NULL)return NULL;
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for(bp = buffer, sp = strtext; *sp != '\0'; bp++, sp++)
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{
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switch(state)
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{
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case 0:
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if(*sp == '\\')state=1;
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*bp = *sp;
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break;
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case 1:
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if(*sp == '\'') /* state=5 */
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{ /* replace \' with 39 */
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bp--;
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*bp = 39;
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buflen--;
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state=0;
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}
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else if(*sp == '\\') /* state=6 */
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{ /* replace \\ with 92 */
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bp--;
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*bp = 92;
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buflen--;
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state=0;
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}
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else
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{
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if(*sp == '0')state=2;
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else state=0;
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*bp = *sp;
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}
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break;
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case 2:
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if(*sp == '0')state=3;
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else state=0;
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*bp = *sp;
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break;
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case 3:
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if(*sp == '0') /* state=4 */
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{
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bp -= 3;
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*bp = 0;
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buflen -= 3;
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state=0;
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}
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else
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{
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*bp = *sp;
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state=0;
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}
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break;
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}
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}
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realloc(buffer,buflen);
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*retbuflen=buflen;
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return buffer;
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}
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/* ----------------
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* Space management for PGresult.
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*
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@ -7,7 +7,7 @@
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* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $Id: libpq-fe.h,v 1.80 2001/11/08 20:37:52 momjian Exp $
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* $Id: libpq-fe.h,v 1.81 2002/03/04 23:59:14 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -252,6 +252,9 @@ extern PQnoticeProcessor PQsetNoticeProcessor(PGconn *conn,
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extern size_t PQescapeString(char *to, const char *from, size_t length);
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extern unsigned char *PQescapeBytea(unsigned char *bintext, size_t binlen,
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size_t *bytealen);
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extern unsigned char *PQunescapeBytea(unsigned char *strtext,
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size_t *retbuflen);
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/* Simple synchronous query */
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extern PGresult *PQexec(PGconn *conn, const char *query);
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