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Diffstat (limited to 'man3/posix_fallocate.3')
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diff --git a/man3/posix_fallocate.3 b/man3/posix_fallocate.3 deleted file mode 100644 index f70d27c..0000000 --- a/man3/posix_fallocate.3 +++ /dev/null @@ -1,181 +0,0 @@ -'\" t -.\" Copyright (c) 2006, Michael Kerrisk <mtk.manpages@gmail.com> -.\" -.\" SPDX-License-Identifier: Linux-man-pages-copyleft -.\" -.TH posix_fallocate 3 2023-10-31 "Linux man-pages 6.7" -.SH NAME -posix_fallocate \- allocate file space -.SH LIBRARY -Standard C library -.RI ( libc ", " \-lc ) -.SH SYNOPSIS -.nf -.B #include <fcntl.h> -.P -.BI "int posix_fallocate(int " fd ", off_t " offset ", off_t " len ); -.fi -.P -.ad l -.RS -4 -Feature Test Macro Requirements for glibc (see -.BR feature_test_macros (7)): -.RE -.P -.BR posix_fallocate (): -.nf - _POSIX_C_SOURCE >= 200112L -.fi -.SH DESCRIPTION -The function -.BR posix_fallocate () -ensures that disk space is allocated for the file referred to by the -file descriptor -.I fd -for the bytes in the range starting at -.I offset -and continuing for -.I len -bytes. -After a successful call to -.BR posix_fallocate (), -subsequent writes to bytes in the specified range are -guaranteed not to fail because of lack of disk space. -.P -If the size of the file is less than -.IR offset + len , -then the file is increased to this size; -otherwise the file size is left unchanged. -.SH RETURN VALUE -.BR posix_fallocate () -returns zero on success, or an error number on failure. -Note that -.I errno -is not set. -.SH ERRORS -.TP -.B EBADF -.I fd -is not a valid file descriptor, or is not opened for writing. -.TP -.B EFBIG -.I offset+len -exceeds the maximum file size. -.TP -.B EINTR -A signal was caught during execution. -.TP -.B EINVAL -.I offset -was less than 0, or -.I len -was less than or equal to 0, or the underlying filesystem does not -support the operation. -.TP -.B ENODEV -.I fd -does not refer to a regular file. -.TP -.B ENOSPC -There is not enough space left on the device containing the file -referred to by -.IR fd . -.TP -.B EOPNOTSUPP -The filesystem containing the file referred to by -.I fd -does not support this operation. -This error code can be returned by C libraries that don't perform the -emulation shown in NOTES, such as musl libc. -.TP -.B ESPIPE -.I fd -refers to a pipe. -.SH ATTRIBUTES -For an explanation of the terms used in this section, see -.BR attributes (7). -.TS -allbox; -lb lb lbx -l l l. -Interface Attribute Value -T{ -.na -.nh -.BR posix_fallocate () -T} Thread safety T{ -.na -.nh -MT-Safe (but see NOTES) -T} -.TE -.SH STANDARDS -POSIX.1-2008. -.SH HISTORY -glibc 2.1.94. -POSIX.1-2001 -.P -POSIX.1-2008 says that an implementation -.I shall -give the -.B EINVAL -error if -.I len -was 0, or -.I offset -was less than 0. -POSIX.1-2001 says that an implementation -.I shall -give the -.B EINVAL -error if -.I len -is less than 0, or -.I offset -was less than 0, and -.I may -give the error if -.I len -equals zero. -.SH CAVEATS -In the glibc implementation, -.BR posix_fallocate () -is implemented using the -.BR fallocate (2) -system call, which is MT-safe. -If the underlying filesystem does not support -.BR fallocate (2), -then the operation is emulated with the following caveats: -.IP \[bu] 3 -The emulation is inefficient. -.IP \[bu] -There is a race condition where concurrent writes from another thread or -process could be overwritten with null bytes. -.IP \[bu] -There is a race condition where concurrent file size increases by -another thread or process could result in a file whose size is smaller -than expected. -.IP \[bu] -If -.I fd -has been opened with the -.B O_APPEND -or -.B O_WRONLY -flags, the function fails with the error -.BR EBADF . -.P -In general, the emulation is not MT-safe. -On Linux, applications may use -.BR fallocate (2) -if they cannot tolerate the emulation caveats. -In general, this is -only recommended if the application plans to terminate the operation if -.B EOPNOTSUPP -is returned, otherwise the application itself will need to implement a -fallback with all the same problems as the emulation provided by glibc. -.SH SEE ALSO -.BR fallocate (1), -.BR fallocate (2), -.BR lseek (2), -.BR posix_fadvise (2) |