Обсуждение: How to check the postgresql version

Hi,
  Sorry if this problem seems stupid but I would appreciate it if 
someone helps.
  I've been implementing several user-defined types and their 
corresponding GiST index in postgresql 7.4.3. They worked well. However, 
I have noticed there are several changes in SPI functions and their 
parameters in 8.0beta. I want to be able to compile my codes in 
Postgresql 7.4.X and 8.0.X, so the only way to do that is to use the C 
preprocessor directives to check PG_VERSION (defined in pg_config.h).
  My problem is: I can't find a way to compare strings in C 
preprocessor directive since PG_VERSION is defined as something like 
"7.4.3" or "7.4.6". I ultimately want to do the following things:

#if PG_VERSION starts with "8.X" ... call 8.0 compatible functions
#else ... call 7.4.x compatible functions
#endif
  Could anyone tell me how to do this kind of version check task? 
Thank you very much.

Ruey-Lung Hsiao

Ruey-Lung Hsiao wrote:
>   My problem is: I can't find a way to compare strings in C preprocessor 
> directive since PG_VERSION is defined as something like "7.4.3" or 
> "7.4.6".

You could try using CATALOG_VERSION_NO in src/include/catversion.h as a 
substitute for the version number.

I think it would probably be a good idea to add a PG_VERSION-workalike 
that is more amenable to use with cpp, though.

-Neil

Neil Conway wrote:
> Ruey-Lung Hsiao wrote:
>>   My problem is: I can't find a way to compare strings in C 
>> preprocessor directive since PG_VERSION is defined as something like 
>> "7.4.3" or "7.4.6".
> 
> You could try using CATALOG_VERSION_NO in src/include/catversion.h as a 
> substitute for the version number.

Along those lines, this is what I've been using in PL/R:

#if (CATALOG_VERSION_NO <= 200211021)
#define PG_VERSION_73_COMPAT
#elif (CATALOG_VERSION_NO <= 200310211)
#define PG_VERSION_74_COMPAT
#else
#define PG_VERSION_80_COMPAT
#endif

I wasn't following this thread earlier, but if you need to distinguish 
between, for example, 7.4.3 and 7.4.6, the above won't help. If you just 
need major Postgres version, it works well.

> I think it would probably be a good idea to add a PG_VERSION-workalike 
> that is more amenable to use with cpp, though.

I agree. As an example, here's how it's done for R:

/* * R version is calculated thus: *   Maj * 65536 + Minor * 256 + Build * 1 * So: * version 1.8.0 results in: *   (1 *
65536)+ (8 * 256) + (0 * 1) == 67584 * version 1.9.0 results in: *   (1 * 65536) + (9 * 256) + (0 * 1) == 67840 */
 

Joe

Joe Conway wrote:
> Along those lines, this is what I've been using in PL/R:
> 
> #if (CATALOG_VERSION_NO <= 200211021)
> #define PG_VERSION_73_COMPAT
> #elif (CATALOG_VERSION_NO <= 200310211)
> #define PG_VERSION_74_COMPAT
> #else
> #define PG_VERSION_80_COMPAT
> #endif
> 
> I wasn't following this thread earlier, but if you need to distinguish 
> between, for example, 7.4.3 and 7.4.6, the above won't help. If you just 
> need major Postgres version, it works well.
> 
PL/Java used to have this in the Makefile.

SS_VERSION := $(subst ., ,$(subst devel,.devel,$(VERSION)))
PGSQL_MAJOR_VER    = $(word 1,$(SS_VERSION))
PGSQL_MINOR_VER    = $(word 2,$(SS_VERSION))
PGSQL_PATCH_VER    = $(word 3,$(SS_VERSION))

override CPPFLAGS := \-DPGSQL_MAJOR_VER=$(PGSQL_MAJOR_VER) \-DPGSQL_MINOR_VER=$(PGSQL_MINOR_VER)
\-DPGSQL_PATCH_VER=$(PGSQL_MINOR_VER)

but I later removed the PGSQL_PATCH_VER since I don't plan to support 
different binaries for different patch levels. I'll try to do that using 
a more dynamic approach (i.e. through "SELECT version").

In the code, I do things like:

#if PGSQL_MAJOR_VER >= 8

or

#if PGSQL_MAJOR_VER == 7 && PGSQL_MINOR_VER < 3

Regards,
Thomas Hallgren

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It's not quite the same, but check out the libpq function
PQserverVersion, which returns the version in a standard
6-digit format, which can then be used to easily do
numeric comparisons. Look for "sversion" in interfaces/libpq/fe-exec.c
and PQserverVersion in interfaces/libpq/fe-connect.c for
more details.
- --
Greg Sabino Mullane greg@turnstep.com
PGP Key: 0x14964AC8 200411222127
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