version.c

Advanced UNIX Programming is the long-awaited (19 years!) update to the 1985 original. Maybe "update

/*
	POSIX System Capabilities
	AUP2, Sec. 1.5.4 (not in book)
	Not written by Marc Rochkind.

	The Example Files are provided "as is," without any warranty;
	without even the implied warranty of merchantability or fitness
	for a particular purpose. The author and his publisher are not
	responsible for any damages, direct or incidental, resulting
	from the use or non-use of these Example Files.

	The Example Files may contain defects, and some contain deliberate
	coding mistakes that were included for educational reasons.
	You are responsible for determining if and how the Example Files
	are to be used.

*/
#if defined(FREEBSD) || defined(DARWIN) /* won't compile on FREEBSD or DARWIN */
										/* Didn't use BSD_DERIVED, because it's possible
										   that a system like that will work.
										*/
#include "defs.h"

int main(void)
{
	printf("Not supported on FreeBSD.\n");
	exit(EXIT_FAILURE);
}
#else
/*
	This program was NOT written by Marc Rochkind. It was downloaded
	from:

	http://www.comptechdoc.org/os/linux/programming/c/linux_pgc.html

	and is part of "Linux C and C++ Programmer's Guide"

	Everything below the horizontal line came from that site.

	(MJR changed C++ comments to C and %ld to %ld)

	--------------------------------------------------------------

POSIX System Capabilities
This section explains how to determine if various parts of POSIX are supported by your system. The easiest way to do this is to look at /usr/include/unistd.h on the system. This file will define the _POSIX_SOURCE versions. It may include other header files which include POSIX definitions. One that you should look at is /usr/include/bits/posix_opt.h which should have most of the POSIX definitions. All the below parameters are listed there. However, the most sure way is to run the below program. This is because the /usr/include/inistd.h file may not be the only one available and it may not be used by your system. Also you need to be aware your kernel may not support all the listed functions. It will depend on the library used to compile it and the options used at the compile time. The kernel will have a great affect on the support of POSIX.4 functions since it controls memory allocation and processes, including the signals between them.

The Test Program
The program listing below will output values based on what your system supports. I call it "posixtst.c". This is a tar and gz version of the source and binary program with a small README file with install instructions. posixtst-1.0.0
*/
#define _POSIX_SOURCE
#define _POSIX_C_SOURCE 199309
#include <unistd.h>
#include <stdio.h> /* mjr */
long val;
int errno;

int main(void) /* mjr */
{
#ifndef _POSIX_VERSION
   printf("No support for POSIX on this system!\n");
#else     /*see what POSIX version*/
   printf("POSIX_VERSION = %ld.\n",_POSIX_VERSION);
   printf("POSIX2_VERSION = %ld.\n",_POSIX2_VERSION);
   printf("POSIX2_C_VERSION = %ld.\n",_POSIX2_C_VERSION);
   #if _POSIX_VERSION == 199009
      printf("This system supports POSIX.1 without support for POSIX.4.\n");
   #else
      #if _POSIX_VERSION >= 199309
         printf ("This system supports POSIX.1 and POSIX.4. \n");
      #else
         printf("This system supports a strange POSIX version between 199009 and 199309.\n");
      #endif
	/*DO POSIX.4 tests*/
      printf ("POSIX.4 Options Test Results:\n");
      #ifdef _POSIX_REALTIME_SIGNALS
         printf("   POSIX.4 Additional real time signals are supported.\n");
         #ifdef _POSIX_RTSIG_MAX
            printf("     _POSIX_RTSIG_MAX=%ld Max real time signals.\n",_POSIX_RTSIG_MAX);
         #else
            printf("     No _POSIX_RTSIG_MAX value exists.\n");
         #endif
         #ifdef _POSIX_SIGQUEUE_MAX
            printf("     _POSIX_SIGQUEUE_MAX=%ld Max real time signals at once per process.\n",_POSIX_RTQUEUE_MAX);
         #else
            printf("     No _POSIX_SIGQUEUE_MAX value exists.\n");
         #endif
      #else
         printf("   POSIX.4 Additional real time signals are not supported.\n");
      #endif
      #ifdef _POSIX_PRIORITY_SCHEDULING
         printf("   POSIX.4 Priority scheduling is supported.\n");
      #else
         printf("   POSIX.4 Priority scheduling is not supported.\n");
      #endif
      #ifdef _POSIX_TIMERS
         printf("   POSIX.4 Clocks and timers are supported.\n");
         #ifdef _POSIX_TIMER_MAX
            printf("     _POSIX_TIMER_MAX=%ld Max number of concurrent timers a process can have.\n",_POSIX_TIMER_MAX);
         #else
            printf("     No _POSIX_TIMER_MAX value exists.\n");
         #endif
         #ifdef _POSIX_DELAYTIMER_MAX
            printf("     _POSIX_DELAYTIMER_MAX=%ld Max number of times a timer can have a detectable overrun.\n",_POSIX_DELAYTIMER_MAX);
         #else
            printf("     No _POSIX_DELAYTIMER_MAX value exists.\n");
         #endif
      #else
         printf("   POSIX.4 Clocks and timers are not supported.\n");
      #endif
      #ifdef _POSIX_ASYNCHRONOUS_IO
         printf("   POSIX.4 Asynchronous I/O is supported.\n");
         #ifdef _POSIX_AIO_LISTIO_MAX
            printf("     _POSIX_AIO_LISTIO_MAX=%ld Max operations in one call\n",_POSIX_AIO_LISTIO_MAX);
         #else
            printf("     No _POSIX_AIO_LISTIO_MAX value exists.\n");
         #endif
         #ifdef _POSIX_AIO_MAX
            printf("     _POSIX_AIO_MAX=%ld Max concurrent Async I/Os\n",_POSIX_AIO_MAX);
         #else
            printf("     No _POSIX_AIO_MAX value exists.\n");
         #endif
      #else
         printf("   POSIX.4 Asynchronous I/O is not supported.\n");
      #endif
      #ifdef _POSIX_SYNCHRONIZED_IO  /*Only supported if Asynchronous I/O is supported*/
         printf("   POSIX.4 Synchronized I/O is supported.\n");
      #else
         printf("   POSIX.4 Synchronized I/O is not supported.\n");
      #endif
      #ifdef _POSIX_PRIORITIZED_IO
         printf("   POSIX.4 Prioritized asynchronous I/O is supported.\n");
         #ifdef _POSIX_AIO_PRIO_DELTA_MAX
            printf("     _POSIX_AIO_PRIO_DELTA_MAX=%ld Max amount AIO priority can be decreased.\n",_POSIX_AIO_PRIO_DELTA_MAX);
         #else
            printf("     No _POSIX_AIO_PRIO_DELTA_MAX value exists.\n");
         #endif
      #else
         printf("   POSIX.4 Prioritized asynchronous I/O is not supported.\n");
      #endif
      #ifdef _POSIX_FSYNC
         printf("   POSIX.4 The fsync function is supported.\n");
      #else
         printf("   POSIX.4 The fsync function is not supported.\n");
      #endif
      #ifdef _POSIX_MAPPED_FILES
         printf("   POSIX.4 Mapping files as memory is supported.\n");
      #else
         printf("   POSIX.4 Mapping files as memory is not supported.\n");
      #endif
      #ifdef _POSIX_MEMLOCK
         printf("   POSIX.4 Locking memory is supported.\n");
      #else
         printf("   POSIX.4 Locking memory is not supported.\n");
      #endif
      #ifdef _POSIX_MEMLOCK_RANGE
         printf("   POSIX.4 Locking memory ranges is supported.\n");
      #else
         printf("   POSIX.4 Locking memory ranges is not supported.\n");
      #endif
      #ifdef _POSIX_MEMORY_PROTECTION
         printf("   POSIX.4 Setting memory protection is supported.\n");
      #else
         printf("   POSIX.4 Setting memory protection is not supported.\n");
      #endif
      #ifdef _POSIX_MESSAGE_PASSING
         printf("   POSIX.4 Message Queues are supported.\n");
         #ifdef _POSIX_MQ_OPEN_MAX
            printf("     _POSIX_MQ_OPEN_MAX=%ld Max # of message queues per process.\n",_POSIX_MQ_OPEN_MAX);
         #else
            printf("     No _POSIX_MQ_OPEN_MAX value exists.\n");
         #endif
         #ifdef _POSIX_MQ_PRIO_MAX
            printf("     _POSIX_MQ_PRIO_MAX=%ld Max # of message priorities.\n",_POSIX_MQ_PRIO_MAX);
         #else
            printf("     No _POSIX_MQ_PRIO_MAX value exists.\n");
         #endif
      #else
         printf("   POSIX.4 Message Queues are not supported.\n");
      #endif
      #ifdef _POSIX_SEMAPHORES
         printf("   POSIX.4 Semaphores are supported.\n");
         #ifdef _POSIX_SEM_NSEMS_MAX
            printf("     _POSIX_SEM_NSEMS_MAX=%ld Max # of open semaphores per process.\n",_POSIX_SEM_NSEMS_MAX);
         #else
            printf("     No _POSIX_SEM_NSEMS_MAX value exists.\n");
         #endif
         #ifdef _POSIX_SEM_VALUE_MAX
            printf("     _POSIX_SEM_VALUE_MAX=%ld Maximum semaphore value.\n",_POSIX_SEM_VALUE_MAX);
         #else
            printf("     No _POSIX_SEM_VALUE_MAX value exists.\n");
         #endif
      #else
         printf("   POSIX.4 Semaphores are not supported.\n");
      #endif
      #ifdef _POSIX_SHARED_MEMORY_OBJECTS
         printf("   POSIX.4 Shared memory objects are supported.\n");
      #else
         printf("   POSIX.4 Shared memory objects are not supported.\n");
      #endif

      #ifdef _POSIX_THREADS
         printf("   POSIX.1c pthreads are supported.\n");
      #else
         printf("   POSIX.1c pthreads are not supported.\n");
      #endif
      #ifdef _POSIX_THREAD_ATTR_STACKADDRTHREAD_ATTR_STACKADDR
         printf("   POSIX.4 Thread stack address attribute option is supported.\n");
      #else
         printf("   POSIX.4 Thread stack address attribute option is not supported.\n");
      #endif
      #ifdef _POSIX_THREAD_ATTR_STACKSIZE
         printf("   POSIX.4 Thread stack size attribute option is supported.\n");
      #else
         printf("   POSIX.4 Thread stack size attribute option is not supported.\n");
      #endif
      #ifdef _POSIX_THREAD_SAFE_FUNCTIONS
         printf("   POSIX.4 Thread-safe functions are supported.\n");
      #else
         printf("   POSIX.4 Thread-safe functions are not supported.\n");
      #endif
      #ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
         printf("   	POSIX.1c thread execution scheduling is supported.\n");
      #else
         printf("   	POSIX.1c thread execution scheduling is not supported.\n");
      #endif
      #ifdef _POSIX_THREAD_PRIO_INHERIT
         printf("   POSIX.4 Thread priority inheritance option is supported.\n");
      #else
         printf("   POSIX.4 Thread priority inheritance option is not supported.\n");
      #endif
      #ifdef _POSIX_THREAD_PROCESS_SHARED
         printf("   POSIX.4 Process-shared synchronization is supported.\n");
      #else
         printf("   POSIX.4 Process-shared synchronization is not supported.\n");
      #endif
      #ifdef _POSIX_POSIX_PII
         printf("   Protocol-independent interfaces are supported.\n");
      #else
         printf("   Protocol-independent interfaces are not supported.\n");
      #endif
      #ifdef _POSIX_PII_XTI
         printf("   XTI protocol-indep. interfaces are supported.\n");
      #else
         printf("   XTI protocol-indep. interfaces are not supported.\n");
      #endif
      #ifdef _POSIX_PII_SOCKET
         printf("   Socket protocol-indep. interfaces are supported.\n");
      #else
         printf("   Socket protocol-indep. interfaces are not supported.\n");
      #endif
      #ifdef _POSIX_PII_INTERNET
         printf("   Internet family of protocols is supported.\n");
      #else
         printf("   Internet family of protocols is not supported.\n");
      #endif
      #ifdef _POSIX_PII_INTERNET_STREAM
         printf("   Connection-mode Internet protocol is supported.\n");
      #else
         printf("   Connection-mode Internet protocol is not supported.\n");
      #endif
      #ifdef _POSIX_PII_INTERNET_DGRAM
         printf("   Connectionless Internet protocol is supported.\n");
      #else
         printf("   Connectionless Internet protocol is not supported.\n");
      #endif
      #ifdef _POSIX_PII_OSI
         printf("   	ISO/OSI family of protocols is supported.\n");
      #else
         printf("   	ISO/OSI family of protocols is not supported.\n");
      #endif
      #ifdef _POSIX_PII_OSI_COTS
         printf("   Connection-mode ISO/OSI service is supported.\n");
      #else
         printf("   Connection-mode ISO/OSI service is not supported.\n");
      #endif
      #ifdef _POSIX_PII_OSI_CLTS
         printf("   Connectionless ISO/OSI service is supported.\n");
      #else
         printf("   Connectionless ISO/OSI service is not supported.\n");
      #endif
      #ifdef _POSIX_POLL
         printf("   Implementation supports `poll' function.\n");
      #else
         printf("   poll function is not  supported.\n");
      #endif
      #ifdef _POSIX_SELECT
         printf("   Implementation supports `select' and `pselect'.\n");
      #else
         printf("   Implementation does not support `select' and `pselect'.\n");
      #endif
      #ifdef _XOPEN_REALTIME
         printf("   X/Open realtime support is available.\n");
      #else
         printf("   X/Open realtime support is not available..\n");
      #endif
      #ifdef _XOPEN_REALTIME_THREADS
         printf("   X/Open realtime thread support is available.\n");
      #else
         printf("   X/Open realtime thread support is not available.\n");
      #endif
      #ifdef _XOPEN_SHM
         printf("   XPG4.2 Shared memory interface is supported.\n");
      #else
         printf("   XPG4.2 Shared memory interface is not supported.\n");
      #endif
      #ifdef _XBS5_ILP32_OFF32
         printf("   32-bit int, long, pointer, and off_t types are supported.\n");
      #else
         printf("   32-bit int, long, pointer, and off_t types are not supported.\n");
      #endif
      #ifdef _XBS5_ILP32_OFFBIG
         printf("   32-bit int, long, and pointer and off_t with at least 64 bits is supported.\n");
      #else
         printf("   32-bit int, long, and pointer and off_t with at least 64 bits is not supported.\n");
      #endif
      #ifdef _XBS5_LP64_OFF64
         printf("   32-bit int, and 64-bit long, pointer, and off_t types are supported.\n");
      #else
         printf("   32-bit int, and 64-bit long, pointer, and off_t types are not supported.\n");
      #endif
      #ifdef _XBS5_LPBIG_OFFBIG
         printf("   32 bits int and long, pointer, and off_t with at least 64 bits are supported.\n");
      #else
         printf("   32 bits int and long, pointer, and off_t with at least 64 bits are not supported.\n");
      #endif


   #endif
   /*Do POSIX.1 tests*/
   printf ("POSIX.1 Options Test Results:\n");
   #ifdef _POSIX_JOB_CONTROL
      printf("   POSIX.1 Job control is supported.\n");
   #else
      printf("   POSIX.1 Job control is not supported.\n");
   #endif
   #ifdef _POSIX_CHOWN_RESTRICTED
      printf("   POSIX.1 Chown restrictions are supported.\n");
   #else
      printf("   POSIX.1 Chown restrictions are not supported.\n");
   #endif
   #ifdef _POSIX_SAVED_IDS
      printf("   POSIX.1 Process saved IDs are supported.\n");
   #else
      printf("   POSIX.1 Process saved IDs are not supported.\n");
   #endif
   #ifdef _POSIX_NO_TRUNC
      printf("   POSIX.1 Long pathname errors are supported.\n");
   #else
      printf("   POSIX.1 Long pathname errors are not supported.\n");
   #endif
   #ifdef _POSIX_VDISABLE
      printf("   POSIX.1 Some terminal charactistics disabling is supported.\n");
   #else
      printf("   POSIX.1 Some terminal charactistics disabling is not supported.\n");
   #endif
   #ifdef NGROUPS_MAX
      printf("   POSIX.1 Supplementary group IDs is supported.\n");
   #else
      printf("   POSIX.1 Supplementary group IDs is not supported.\n");
   #endif

#endif

   /*System Run time testing*/
   printf("\nSystem run time tests:\n");
   errno=0;
   val=sysconf(_SC_JOB_CONTROL);
   if ((val == -1) && (errno))
   {
     printf("Bad option _SC_JOB_CONTROL\n");
   }
   else if ((val == -1) && (!errno))
   {
     printf("POSIX.1 JOB CONTROL not Supported.\n");
   }
   else
   {
     printf("POSIX.1 JOB CONTROL Supported.\n");
   }
   errno=0;
   val=sysconf(_SC_SAVED_IDS);
   if ((val == -1) && (errno))
   {
     printf("Bad option _SC_SAVED_IDS\n");
   }
   else if ((val == -1) && (!errno))
   {
     printf("POSIX.1 SAVED IDS not Supported.\n");
   }
   else
   {
     printf("POSIX.1 SAVED IDS Supported.\n");
   }
   errno=0;
   val=sysconf(_SC_VERSION);