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

NAME

       extendedFILE - enable extended FILE facility usage

SYNOPSIS

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

DESCRIPTION

       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 func-
       tions. 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 enable_extended_FILE_stdio(3C).

       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).

ENVIRONMENT VARIABLES

       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 cor-
			      ruption. 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 environment 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.

EXAMPLES

       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 structures 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
	 $ _STDIO_BADFD=100 _STDIO_BADFD_SIGNAL=SIGABRT 
	    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:

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

FILES

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

ATTRIBUTES

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

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

SEE ALSO

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

WARNINGS

       The following displayed message

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

       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)