diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index d3e87056f2c..e69feacfe6a 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -262,6 +262,41 @@ PGconn *PQsetdb(char *pghost,
+
+ PQsocketPollPQsocketPoll
+
+
+ nonblocking connection
+ Poll a connection's underlying socket descriptor retrieved with .
+
+int PQsocketPoll(int sock, int forRead, int forWrite, time_t end_time);
+
+
+
+
+ This function sets up polling of a file descriptor. The underlying function is either
+ poll(2) or select(2), depending on platform
+ support. The primary use of this function is iterating through the connection sequence
+ described in the documentation of . If
+ forRead is specified, the function waits for the socket to be ready
+ for reading. If forWrite is specified, the function waits for the
+ socket to be ready for write. See POLLIN and POLLOUT
+ from poll(2), or readfds and
+ writefds from select(2) for more information. If
+ end_time is not -1, it specifies the time at which
+ this function should stop waiting for the condition to be met.
+
+
+
+ The function returns a value greater than 0 if the specified condition
+ is met, 0 if a timeout occurred, or -1 if an error
+ occurred. The error can be retrieved by checking the errno(3) value. In
+ the event forRead and forWrite are not set, the
+ function immediately returns a timeout condition.
+
+
+
+
PQconnectStartParamsPQconnectStartParams
PQconnectStartPQconnectStart
@@ -358,7 +393,10 @@ PostgresPollingStatusType PQconnectPoll(PGconn *conn);
Loop thus: If PQconnectPoll(conn) last returned
PGRES_POLLING_READING, wait until the socket is ready to
read (as indicated by select(), poll(), or
- similar system function).
+ similar system function). Note that PQsocketPoll
+ can help reduce boilerplate by abstracting the setup of
+ select(2) or poll(2) if it is
+ available on your system.
Then call PQconnectPoll(conn) again.
Conversely, if PQconnectPoll(conn) last returned
PGRES_POLLING_WRITING, wait until the socket is ready
diff --git a/src/interfaces/libpq/exports.txt b/src/interfaces/libpq/exports.txt
index 9fbd3d34074..1e48d37677d 100644
--- a/src/interfaces/libpq/exports.txt
+++ b/src/interfaces/libpq/exports.txt
@@ -202,3 +202,4 @@ PQcancelSocket 199
PQcancelErrorMessage 200
PQcancelReset 201
PQcancelFinish 202
+PQsocketPoll 203
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index f2fc78a481c..f562cd8d344 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -55,7 +55,6 @@ static int pqPutMsgBytes(const void *buf, size_t len, PGconn *conn);
static int pqSendSome(PGconn *conn, int len);
static int pqSocketCheck(PGconn *conn, int forRead, int forWrite,
time_t end_time);
-static int pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time);
/*
* PQlibVersion: return the libpq version number
@@ -1059,7 +1058,7 @@ pqSocketCheck(PGconn *conn, int forRead, int forWrite, time_t end_time)
/* We will retry as long as we get EINTR */
do
- result = pqSocketPoll(conn->sock, forRead, forWrite, end_time);
+ result = PQsocketPoll(conn->sock, forRead, forWrite, end_time);
while (result < 0 && SOCK_ERRNO == EINTR);
if (result < 0)
@@ -1083,8 +1082,8 @@ pqSocketCheck(PGconn *conn, int forRead, int forWrite, time_t end_time)
* Timeout is infinite if end_time is -1. Timeout is immediate (no blocking)
* if end_time is 0 (or indeed, any time before now).
*/
-static int
-pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time)
+int
+PQsocketPoll(int sock, int forRead, int forWrite, time_t end_time)
{
/* We use poll(2) if available, otherwise select(2) */
#ifdef HAVE_POLL
diff --git a/src/interfaces/libpq/libpq-fe.h b/src/interfaces/libpq/libpq-fe.h
index 09b485bd2bc..8d3c5c6f662 100644
--- a/src/interfaces/libpq/libpq-fe.h
+++ b/src/interfaces/libpq/libpq-fe.h
@@ -21,6 +21,7 @@ extern "C"
#endif
#include
+#include
/*
* postgres_ext.h defines the backend's externally visible types,
@@ -670,6 +671,9 @@ extern int lo_export(PGconn *conn, Oid lobjId, const char *filename);
/* Get the version of the libpq library in use */
extern int PQlibVersion(void);
+/* Poll a socket for reading and/or writing with an optional timeout */
+extern int PQsocketPoll(int sock, int forRead, int forWrite, time_t end_time);
+
/* Determine length of multibyte encoded char at *s */
extern int PQmblen(const char *s, int encoding);