pathconf(3)

1FPATHCONF(3)               Linux Programmer's Manual              FPATHCONF(3)
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NAME

6       fpathconf, pathconf - get configuration values for files
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SYNOPSIS

9       #include <unistd.h>
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11       long fpathconf(int fd, int name);
12       long pathconf(char *path, int name);
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DESCRIPTION

15       fpathconf() gets a value for the configuration option name for the open
16       file descriptor fd.
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18       pathconf() gets a value for configuration option name for the  filename
19       path.
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21       The  corresponding  macros defined in <unistd.h> are minimum values; if
22       an application wants to take advantage of values which  may  change,  a
23       call  to  fpathconf()  or  pathconf() can be made, which may yield more
24       liberal results.
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26       Setting name equal to one of the following constants returns  the  fol‐
27       lowing configuration options:
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29       _PC_LINK_MAX
30              returns  the maximum number of links to the file.  If fd or path
31              refer to a directory, then the value applies to the whole direc‐
32              tory.  The corresponding macro is _POSIX_LINK_MAX.
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34       _PC_MAX_CANON
35              returns  the  maximum length of a formatted input line, where fd
36              or path must refer to a terminal.  The  corresponding  macro  is
37              _POSIX_MAX_CANON.
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39       _PC_MAX_INPUT
40              returns  the  maximum  length of an input line, where fd or path
41              must  refer  to  a  terminal.   The   corresponding   macro   is
42              _POSIX_MAX_INPUT.
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44       _PC_NAME_MAX
45              returns  the  maximum length of a filename in the directory path
46              or fd that the process is allowed to create.  The  corresponding
47              macro is _POSIX_NAME_MAX.
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49       _PC_PATH_MAX
50              returns  the  maximum length of a relative pathname when path or
51              fd is the current working directory.  The corresponding macro is
52              _POSIX_PATH_MAX.
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54       _PC_PIPE_BUF
55              returns  the  size  of the pipe buffer, where fd must refer to a
56              pipe or FIFO and path must refer to a FIFO.   The  corresponding
57              macro is _POSIX_PIPE_BUF.
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59       _PC_CHOWN_RESTRICTED
60              returns  non-zero  if  the chown(2) call may not be used on this
61              file.  If fd or path refer to a directory, then this applies  to
62              all  files  in  that  directory.   The  corresponding  macro  is
63              _POSIX_CHOWN_RESTRICTED.
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65       _PC_NO_TRUNC
66              returns   non-zero   if   accessing   filenames   longer    than
67              _POSIX_NAME_MAX  generates an error.  The corresponding macro is
68              _POSIX_NO_TRUNC.
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70       _PC_VDISABLE
71              returns non-zero if special character  processing  can  be  dis‐
72              abled, where fd or path must refer to a terminal.
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RETURN VALUE

75       The  limit  is  returned, if one exists.  If the system does not have a
76       limit for  the  requested  resource,  -1  is  returned,  and  errno  is
77       unchanged.   If  there is an error, -1 is returned, and errno is set to
78       reflect the nature of the error.
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CONFORMING TO

81       POSIX.1-2001.
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NOTES

84       Files with name lengths longer than the value returned for  name  equal
85       to _PC_NAME_MAX may exist in the given directory.
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87       Some  returned values may be huge; they are not suitable for allocating
88       memory.
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COLOPHON

94       This page is part of release 3.22 of the Linux  man-pages  project.   A
95       description  of  the project, and information about reporting bugs, can
96       be found at http://www.kernel.org/doc/man-pages/.
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100GNU                               1993-04-04                      FPATHCONF(3)