Is there a header identifying SunOS/Solaris version at compile time? - c++

Question

I am trying to detect Solaris/SunOS version at compile time so that I can enable/disable use of port_create() and other APIs.
Is there a header identifying SunOS/Solaris version at compile time?

Answer 1

If no header is giving you this information, you could of course parse the output of uname and generate -D preprocessor option(s) from your build script/makefile/...

Answer 2

Elaborating upon the suggestion by #meaning-matters, one can make a compile-time definition, say SUN_VERSION using the output of uname -r. That actually gives a floating point number, e.g., 5.10, which you could convert into a preprocessor-comparable form using a simple sed command, e.g., this compiler option:
-DSUN_VERSION=`uname -r | sed -e 's/\.\([0-9]\{1,1\}\)$/0\1/' -e 's/\.//'`
produces 510 for 5.10, 509 for 5.9, etc.
In your source program, you could use it like this
#if SUN_VERSION >= 510
(or whatever makes sense).

Answer 3

Identifying the OS release in order to assert an API is available or not is risky if not doomed. You cannot assume an API will stay in future releases nor if it is available in a parallel branch (eg. Illumos vs Solaris 11 which are both reporting SunOS 5.11 as their version).
The usual way to overcome this issue is simply to check if the API is available by compiling a small test source code to figure it out. This is usually done in a script traditionally named configure that builds a Makefile and an include file tailored to your system.

Answer 4

To expand upon #meaning-matters answer, use GNU make, and set a variable to the OS version. Pass that variable on to the compiler using the -D command-line option.
Makefile:
OS_VERSION := $(shell uname -r)
version:
$(CC) -DOS_VERSION=$(OS_VERSION) version.c -o version
test:
echo $(OS_VERSION)
version.c:
#include <stdio.h>
#define STRINGIFY(x) #x
#define TOSTRING(x) STRINGIFY(x)
int main()
{
printf( "OS Version: " TOSTRING(OS_VERSION) "\n" );
return( 0 );
}
Output:
bash 4.1$ gmake test
echo 5.11
5.11
bash 4.1$ gmake version
cc -DOS_VERSION=5.11 version.c -o version
bash 4.1$ ./version
OS Version: 5.11
bash 4.1$
Use := (assign if not already set) to only run the uname command once.
That will show "5.10" for Solaris 10, "5.11" for Solaris 11.