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Treat empty connection parameters as is, in particular to enable overriding 

environment variables with "nothing".  Empty host parameter indicates
Unix socket.
This commit is contained in:
Peter Eisentraut 2000-10-03 19:16:17 +00:00
parent 3189e48470
commit 7c5a444f53
2 changed files with 45 additions and 53 deletions
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75
doc/src/sgml/libpq.sgml
View File

@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.41 2000/09/29 20:21:34 petere Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.42 2000/10/03 19:16:16 petere Exp $
-->
<chapter id="libpq-chapter">
@ -38,21 +38,22 @@ $Header: /cvsroot/pgsql/doc/src/sgml/libpq.sgml,v 1.41 2000/09/29 20:21:34 peter
<filename>libpq</filename> library.
</para>
<sect1 id="libpq-connect">
<title>Database Connection Functions</title>
<sect1 id="libpq-connect">
<title>Database Connection Functions</title>
<para>
The following routines deal with making a connection to
a <productname>Postgres</productname> backend server. The application
program can have several backend connections open at one time.
(One reason to do that is to access more than one database.)
Each connection is represented by a PGconn object which is obtained
from PQconnectdb() or PQsetdbLogin(). Note that these functions
will always return a non-null object pointer, unless perhaps
there is too little memory even to allocate the PGconn object.
The PQstatus function should be called
to check whether a connection was successfully made
before queries are sent via the connection object.
<para>
The following routines deal with making a connection to a
<productname>Postgres</productname> backend server. The
application program can have several backend connections open at
one time. (One reason to do that is to access more than one
database.) Each connection is represented by a
<structname>PGconn</> object which is obtained from
<function>PQconnectdb</> or <function>PQsetdbLogin</>. Note that
these functions will always return a non-null object pointer,
unless perhaps there is too little memory even to allocate the
<structname>PGconn</> object. The <function>PQstatus</> function
should be called to check whether a connection was successfully
made before queries are sent via the connection object.
<itemizedlist>
<listitem>
@ -87,9 +88,8 @@ PGconn *PQconnectdb(const char *conninfo)
<listitem>
<para>
Name of host to connect to. If a non-zero-length string is
specified, TCP/IP
communication is used. Using this parameter causes a hostname look-up.
See hostaddr.
specified, TCP/IP communication is used, else Unix sockets.
Using this parameter causes a hostname look-up. See hostaddr.
</para>
</listitem>
</varlistentry>
@ -1930,22 +1930,22 @@ call <function>fe_setauthsvc</function> at all.
</sect1>
<sect1 id="libpq-sample">
<title>Sample Programs</title>
<sect2>
<title>Sample Program 1</title>
<sect1 id="libpq-example">
<title>Example Programs</title>
<example id="libpq-example-1">
<title>libpq Example Program 1</title>
<para>
<programlisting>
/*
* testlibpq.c Test the C version of Libpq, the Postgres frontend
* testlibpq.c
*
* Test the C version of libpq, the PostgreSQL frontend
* library.
*
*
*/
#include &lt;stdio.h&gt;
#include "libpq-fe.h"
#include &lt;libpq-fe.h&gt;
void
exit_nicely(PGconn *conn)
@ -2065,13 +2065,11 @@ main()
}
</programlisting>
</para>
</sect2>
</example>
<sect2>
<title>Sample Program 2</title>
<example id="libpq-example-2">
<title>libpq Example Program 2</title>
<para>
<programlisting>
/*
* testlibpq2.c
@ -2187,13 +2185,11 @@ main()
return 0;
}
</programlisting>
</para>
</sect2>
</example>
<sect2>
<title>Sample Program 3</title>
<example id="libpq-example-3">
<title>libpq Example Program 3</>
<para>
<programlisting>
/*
* testlibpq3.c Test the C version of Libpq, the Postgres frontend
@ -2370,10 +2366,9 @@ main()
return 0;
}
</programlisting>
</para>
</example>
</sect2>
</sect1>
</sect1>
</chapter>
<!-- Keep this comment at the end of the file

23
src/interfaces/libpq/fe-connect.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.136 2000/10/03 03:39:46 momjian Exp $
* $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-connect.c,v 1.137 2000/10/03 19:16:17 petere Exp $
*
*-------------------------------------------------------------------------
*/
@ -416,15 +416,12 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
if (conn == NULL)
return (PGconn *) NULL;
if ((pghost == NULL) || pghost[0] == '\0')
{
if ((tmp = getenv("PGHOST")) != NULL)
conn->pghost = strdup(tmp);
}
else
if (pghost)
conn->pghost = strdup(pghost);
else if ((tmp = getenv("PGHOST")) != NULL)
conn->pghost = strdup(tmp);
if ((pgport == NULL) || pgport[0] == '\0')
if (pgport == NULL)
{
if ((tmp = getenv("PGPORT")) == NULL)
tmp = DEF_PGPORT_STR;
@ -433,7 +430,7 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
else
conn->pgport = strdup(pgport);
if ((pgtty == NULL) || pgtty[0] == '\0')
if (pgtty == NULL)
{
if ((tmp = getenv("PGTTY")) == NULL)
tmp = DefaultTty;
@ -442,7 +439,7 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
else
conn->pgtty = strdup(pgtty);
if ((pgoptions == NULL) || pgoptions[0] == '\0')
if (pgoptions == NULL)
{
if ((tmp = getenv("PGOPTIONS")) == NULL)
tmp = DefaultOption;
@ -476,7 +473,7 @@ PQsetdbLogin(const char *pghost, const char *pgport, const char *pgoptions,
else
conn->pgpass = strdup(DefaultPassword);
if ((dbName == NULL) || dbName[0] == '\0')
if (dbName == NULL)
{
if ((tmp = getenv("PGDATABASE")) != NULL)
conn->dbName = strdup(tmp);
@ -705,7 +702,7 @@ connectDBStart(PGconn *conn)
MemSet((char *) &conn->raddr, 0, sizeof(conn->raddr));
if (conn->pghostaddr != NULL)
if (conn->pghostaddr != NULL && conn->pghostaddr[0] != '\0')
{
/* Using pghostaddr avoids a hostname lookup */
/* Note that this supports IPv4 only */
@ -724,7 +721,7 @@ connectDBStart(PGconn *conn)
memmove((char *) &(conn->raddr.in.sin_addr),
(char *) &addr, sizeof(addr));
}
else if (conn->pghost != NULL)
else if (conn->pghost != NULL && conn->pghost[0] != '\0')
{
/* Using pghost, so we have to look-up the hostname */
struct hostent *hp;