Martijn van Oosterhout wrote:
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> On Fri, May 12, 2006 at 08:38:07PM -0400, Bruce Momjian wrote:
> > Is this like detecting of libpq is SSL-enabled? I see PQgetssl(). Do
> > we need to add a libpq function to return true/false for threading?
> > Slony requires a threaded libpq, so it could do the test to prevent
> > wrong configurations. It would be nice to enabled threading by default,
> > but it is like SSL in that not all operating systems support it.
>
> PQgetssl() doesn't tell you if SSL is supported, it tells you if the
> *current connection* is using OpenSSL, which is similar but not the
> same.
>
> There is AFAIK no way to tell if SSL support is compiled in. Part of
> the patch I posted for GnuTLS support answered this question also
> (PQgettlsinfo()).
I thought about this. Attached is a patch you can use to
popen("pg_config") and then look for the thread flag to configure. One
idea would be to add this sample to our libpq documentation. The
problem with the example is popen() overhead, pg_config not in $PATH, or
pg_config's version not matching libpq's version.
A more comprehensive idea would be to embed the configure string in
libpq, like we do for pg_config, and allow that to be returned to the
caller so they can do a strstr() to see if a certain flag was used.
Having per-configure flag functions, like for threading, seems like it
could be a mess because there is a lot more application programmers might
care about in addition to threading, like SSL, multi-byte, etc.
--
Bruce Momjian http://candle.pha.pa.us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
/*
* This function queries pg_config to check for specific
* configure flags used to build PostgreSQL. It can be
* easily modified to return true/false to the caller.
* This example tests thread safety.
*/
#include <stdio.h>
#include <string.h>
#define PG_CONFIG_CMD "pg_config --configure"
/*
* pg_config's output should fit in one string because we don't want
* the search string to split across reads.
*/
#define POPEN_READ 8192
int
main(int argc, char *argv[])
{
FILE *p;
char str[POPEN_READ];
if ((p = popen(PG_CONFIG_CMD, "r")) == NULL ||
fgets(str, POPEN_READ, p) == NULL)
{
fprintf(stderr, "Cannot run \"%s\", perhaps incorrect $PATH",
PG_CONFIG_CMD);
if (p)
pclose(p);
exit(2);
}
pclose(p);
if (strstr(str, "--enable-thread-safety") != NULL)
{
puts("threading enabled");
return 0;
}
else
{
puts("threading not enabled");
return 1;
}
}
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