extendedFILE(5)

1extendedFILE(5)       Standards, Environments, and Macros      extendedFILE(5)
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NAME

6       extendedFILE - enable extended FILE facility usage
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SYNOPSIS

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

14       The  extendedFILE.so.1  is not a library but an enabler of the extended
15       FILE facility.
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18       The extended FILE facility allows 32-bit processes  to  use  any  valid
19       file  descriptor  with the standard I/O (see stdio(3C)) C library func‐
20       tions. Historically, 32-bit applications have been limited to using the
21       first 256 numerical file descriptors for use with standard I/O streams.
22       By using the extended FILE facility  this  limitation  is  lifted.  Any
23       valid file descriptor can be used with standard I/O. See the NOTES sec‐
24       tion of enable_extended_FILE_stdio(3C).
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27       The extended FILE facility is enabled from the shell  level  before  an
28       application is launched. The file descriptor limit must also be raised.
29       The syntax for raising the file descriptor limit is
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31         $ ulimit -n max_file_descriptors
32         $ LD_PRELOAD_32=/usr/lib/extendedFILE.so.1 application [arg...]
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36       where max_file_descriptors is the maximum number  of  file  descriptors
37       desired.  See  limit(1).  The  maximum value is the same as the maximum
38       value for open(2).
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ENVIRONMENT VARIABLES

41       The  following  environment  variables  control  the  behavior  of  the
42       extended FILE facility.
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44       _STDIO_BADFD           This  variable takes an integer representing the
45                              lowest file descriptor, which will be made unal‐
46                              locatable.  This  action  provides  a protection
47                              mechanism so that applications that abuse inter‐
48                              faces  do not experience silent data corruption.
49                              The value must be between 3 and 255 inclusive.
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52       _STDIO_BADFD_SIGNAL    This variable takes an integer or string  repre‐
53                              senting  any  valid  signal. See signal.h(3HEAD)
54                              for valid values or  strings.  This  environment
55                              variable  causes the specified signal to be sent
56                              to the application if certain exceptional  cases
57                              are  detected  during  the use of this facility.
58                              The default signal is SIGABRT.
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EXAMPLES

62       Example 1 Limit the number of file descriptors and  FILE  standard  I/O
63       structures.
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66       The  following  example  limits the number of file descriptors and FILE
67       standard I/O structures to 1000.
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70         $ ulimit -n 1000
71         $ LD_PRELOAD_32=/usr/lib/extendedFILE.so.1 application [arg...]
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74       Example 2 Enable the extended FILE facility.
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77       The  following  example  enables  the  extended  FILE   facility.   See
78       enable_extended_FILE_stdio(3C) for more examples.
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81         $ ulimit -n 1000
82         $ _STDIO_BADFD=100 _STDIO_BADFD_SIGNAL=SIGABRT \
83            LD_PRELOAD_32=/usr/lib/extendedFILE.so.1  \
84            application [arg ...]
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87       Example  3  Set up the extended FILE environment and start the applica‐
88       tion.
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91       The following shell script first sets up the proper extended FILE envi‐
92       ronment and then starts the application:
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95         #!/bin/sh
96         if [ $# = 0 ]; then
97            echo "usage: $0 application [arguments...]"
98            exit 1
99         fi
100         ulimit -n 1000
101         # _STDIO_BADFD=196; export _STDIO_BADFD
102         # _STDIO_BADFD_SIGNAL=SIGABRT; export _STDIO_BADFD_SIGNAL
103         LD_PRELOAD_32=/usr/lib/extendedFILE.so.1; export LD_PRELOAD_32
104         "$@"
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FILES

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

112       See attributes(5)  for descriptions of the following attributes:
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117       ┌─────────────────────────────┬─────────────────────────────┐
118       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
119       ├─────────────────────────────┼─────────────────────────────┤
120       │Availability                 │SUNWcsl (32-bit)             │
121       ├─────────────────────────────┼─────────────────────────────┤
122       │Interface Stability          │Stable                       │
123       ├─────────────────────────────┼─────────────────────────────┤
124       │MT-Level                     │Safe                         │
125       └─────────────────────────────┴─────────────────────────────┘
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WARNINGS

132       The following displayed message
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134         Application violated extended FILE safety mechanism.
135         Please read the man page for extendedFILE.
136         Aborting
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141       is an indication that your application is modifying the  internal  file
142       descriptor field of the FILE structure from standard I/O. Continued use
143       of this extended FILE facility could harm your data.  Do  not  use  the
144       extended FILE facility with your application.
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148SunOS 5.11                        18 Apr 2006                  extendedFILE(5)