man3/posix_fallocate.3

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  23 .TH POSIX_FALLOCATE 3  2006-03-01 "GNU" "Linux Programmer's Manual"
  24 .SH NAME
  25 posix_fallocate \- allocate file space
  26 .SH SYNOPSIS
  27 .nf
  28 .B #define _XOPEN_SOURCE 600
  29 .B #include <fcnlt.h>
  30 .sp
  31 .BI "int posix_fallocate(int " fd ", off_t " offset ", off_t " len );
  32 .fi
  33 .SH DESCRIPTION
  34 The function
  35 .BR posix_fallocate ()
  36 ensures that disk space is allocated for the file referred to by the
  37 descriptor
  38 .I fd
  39 for the bytes in the range starting at
  40 .I offset
  41 and continuing for
  42 .I len
  43 bytes.
  44 After a successful call to
  45 .BR posix_fallocate (),
  46 subsequent writes to bytes in the specified range are
  47 guaranteed not to fail because of lack of disk space.
  48
  49 If the size of the file is less than
  50 .IR offset + len ,
  51 then the file is increased to this size;
  52 otherwise the file size is left unchanged.
  53 .SH "RETURN VALUE"
  54 .BR posix_fallocate ()
  55 returns zero on success, or an error number on failure.
  56 Note that
  57 .I errno
  58 is not set.
  59 .SH "ERRORS"
  60 .TP
  61 .B EBADF
  62 .I fd
  63 is not a valid file descriptor, or is not opened for writing.
  64 .TP
  65 .B EFBIG
  66 .I offset+len
  67 exceeds the maximum file size.
  68 .TP
  69 .B EINVAL
  70 .I offset
  71 or
  72 .I len
  73 was less than 0.
  74 .TP
  75 .B ENODEV
  76 .I fd
  77 does not refer to a regular file.
  78 .TP
  79 .B ENOSPC
  80 There is not enough space left on the device containing the file
  81 referred to by
  82 .IR fd .
  83 .TP
  84 .B ESPIPE
  85 .I fd
  86 refers to a pipe of file descriptor.
  87 .SH VERSIONS
  88 .BR posix_fallocate ()
  89 is available since glibc 2.1.94.
  90 .SH "CONFORMING TO"
  91 POSIX.1-2001.
  92 .SH "SEE ALSO"
  93 .BR fallocate (2),
  94 .BR lseek (2),
  95 .BR posix_fadvise (2),
  96 .BR feature_test_macros (7)