fdopen(3c) - osol9

1fdopen(3C)               Standard C Library Functions               fdopen(3C)
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NAME

6       fdopen - associate a stream with a file descriptor
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SYNOPSIS

9       #include <stdio.h>
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11       FILE *fdopen(int fildes, const char *mode);
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DESCRIPTION

15       The  fdopen()  function  associates  a  stream  with  a file descriptor
16       fildes.
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19       The mode argument is a character string having  one  of  the  following
20       values:
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25       r or rb               Open a file for reading.
26       w or wb               Open a file for writing.
27       a or ab               Open a file for writing at end of file.
28       r+, rb+ or r+b        Open  a  file  for  update (reading and
29                             writing).
30       w+, wb+ or w+b        Open a file  for  update  (reading  and
31                             writing).
32       a+, ab+ or a+b        Open  a  file  for  update (reading and
33                             writing) at end of file.
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37       The meaning of these flags is exactly as specified  for  the  fopen(3C)
38       function, except that modes beginning with w do not cause truncation of
39       the file. A trailing F character can also be included in the mode argu‐
40       ment as described in fopen(3C) to enable extended FILE facility.
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43       The  mode  of the stream must be allowed by the file access mode of the
44       open file. The file position indicator associated with the  new  stream
45       is set to the position indicated by the file offset associated with the
46       file descriptor.
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49       The fdopen() function preserves the offset maximum previously  set  for
50       the open file description corresponding to  fildes.
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53       The  error  and  end-of-file indicators for the stream are cleared. The
54       fdopen() function may cause the st_atime field of the  underlying  file
55       to be marked for update.
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58       If  fildes refers to a shared memory object, the result of the fdopen()
59       function is unspecified.
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RETURN VALUES

62       Upon successful completion, fdopen() returns a  pointer  to  a  stream.
63       Otherwise,  a null pointer is returned and errno is set to indicate the
64       error.
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67       The fdopen() function may fail and not set errno if there are  no  free
68       stdio streams.
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ERRORS

71       The fdopen() function may fail if:
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73       EBADF     The fildes argument is not a valid file descriptor.
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76       EINVAL    The mode argument is not a valid mode.
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79       EMFILE    {FOPEN_MAX}   streams  are  currently  open  in  the  calling
80                 process.
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82                 {STREAM_MAX}  streams  are  currently  open  in  the  calling
83                 process.
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86       ENOMEM    There is insufficient space to allocate a buffer.
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USAGE

90       A process is allowed to have at least {FOPEN_MAX} stdio streams open at
91       a time. For 32-bit applications, however, the underlying ABIs  formerly
92       required  that  no file descriptor used to access the file underlying a
93       stdio stream have a value greater than 255. To maintain binary compati‐
94       bility  with  earlier  Solaris  releases,  this  limit still constrains
95       32-bit applications.
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98       File descriptors are obtained from calls like open(2), dup(2), creat(2)
99       or  pipe(2),  which  open  files but do not return streams. Streams are
100       necessary input for almost all of the standard I/O library functions.
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ATTRIBUTES

103       See attributes(5) for descriptions of the following attributes:
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108       ┌─────────────────────────────┬─────────────────────────────┐
109       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
110       ├─────────────────────────────┼─────────────────────────────┤
111       │Interface Stability          │See below.                   │
112       ├─────────────────────────────┼─────────────────────────────┤
113       │MT-Level                     │MT-Safe                      │
114       └─────────────────────────────┴─────────────────────────────┘
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117       The F character in the mode argument is Evolving. In all other respects
118       this function is Standard.
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