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OpenSolaris 2009.06 - man page for extendedfile (opensolaris section 5)

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extendedFILE(5) 	       Standards, Environments, and Macros		  extendedFILE(5)

       extendedFILE - enable extended FILE facility usage

       $ ulimit -n N_file_descriptors
       $ LD_PRELOAD_32=/usr/lib/extendedFILE.so.1 application [arg...]

       The extendedFILE.so.1 is not a library but an enabler of the extended FILE facility.

       The  extended  FILE facility allows 32-bit processes to use any valid file descriptor with
       the standard I/O (see stdio(3C)) C library functions.  Historically,  32-bit  applications
       have  been limited to using the first 256 numerical file descriptors for use with standard
       I/O streams.  By using the extended FILE facility this limitation  is  lifted.  Any  valid
       file   descriptor   can	 be   used   with   standard   I/O.  See  the  NOTES  section  of

       The extended FILE facility is enabled from  the	shell  level  before  an  application  is
       launched.  The  file descriptor limit must also be raised. The syntax for raising the file
       descriptor limit is

	 $ ulimit -n max_file_descriptors
	 $ LD_PRELOAD_32=/usr/lib/extendedFILE.so.1 application [arg...]

       where max_file_descriptors  is  the  maximum  number  of  file  descriptors  desired.  See
       limit(1). The maximum value is the same as the maximum value for open(2).

       The following environment variables control the behavior of the extended FILE facility.

       _STDIO_BADFD	      This  variable  takes  an  integer  representing	the  lowest  file
			      descriptor, which will be made unallocatable. This action  provides
			      a  protection  mechanism so that applications that abuse interfaces
			      do not experience silent data corruption. The value must be between
			      3 and 255 inclusive.

       _STDIO_BADFD_SIGNAL    This  variable  takes  an  integer or string representing any valid
			      signal. See signal.h(3HEAD) for valid values or strings. This envi-
			      ronment  variable  causes  the  specified  signal to be sent to the
			      application if certain exceptional cases are  detected  during  the
			      use of this facility. The default signal is SIGABRT.

       Example 1 Limit the number of file descriptors and FILE standard I/O structures.

       The  following  example limits the number of file descriptors and FILE standard I/O struc-
       tures to 1000.

	 $ ulimit -n 1000
	 $ LD_PRELOAD_32=/usr/lib/extendedFILE.so.1 application [arg...]

       Example 2 Enable the extended FILE facility.

       The    following    example    enables	  the	  extended     FILE	facility.     See
       enable_extended_FILE_stdio(3C) for more examples.

	 $ ulimit -n 1000
	    LD_PRELOAD_32=/usr/lib/extendedFILE.so.1  \
	    application [arg ...]

       Example 3 Set up the extended FILE environment and start the application.

       The  following  shell  script  first sets up the proper extended FILE environment and then
       starts the application:

	 if [ $# = 0 ]; then
	    echo "usage: $0 application [arguments...]"
	    exit 1
	 ulimit -n 1000
	 # _STDIO_BADFD=196; export _STDIO_BADFD
	 LD_PRELOAD_32=/usr/lib/extendedFILE.so.1; export LD_PRELOAD_32

       /usr/lib/extendedFILE.so.1    enabling library

       See attributes(5)  for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWcsl (32-bit)		   |
       |Interface Stability	     |Stable			   |
       |MT-Level		     |Safe			   |

       limit(1), open(2), enable_extended_FILE_stdio(3C), fdopen(3C), fopen(3C), popen(3C),  sig-
       nal.h(3HEAD), stdio(3C), attributes(5)

       The following displayed message

	 Application violated extended FILE safety mechanism.
	 Please read the man page for extendedFILE.

       is  an indication that your application is modifying the internal file descriptor field of
       the FILE structure from standard I/O. Continued use of this extended FILE  facility  could
       harm your data.	Do not use the extended FILE facility with your application.

SunOS 5.11				   18 Apr 2006				  extendedFILE(5)
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