Standard C Library Functions                  posixfallocate(3C)



NAME
     posixfallocate - file space control

SYNOPSIS
     #include 

     int posixfallocate(int fd, offt offset, offt len);


DESCRIPTION
     The posixfallocate() function  ensures  that  any  required
     storage  for  regular  file data starting at offset and con-
     tinuing for len  bytes  is  allocated  on  the  file  system
     storage  media.  If  posixfallocate() returns successfully,
     subsequent writes to the specified file data will  not  fail
     due  to  the  lack  of free space on the file system storage
     media.


     If the offset]len is beyond  the  current  file  size,  then
     posixfallocate()  adjusts the file size to offset]len. Oth-
     erwise, the file size is not changed.


     Space allocated with posixfallocate() is freed  by  a  suc-
     cessful  call to creat(2) or open(2) that truncates the size
     of the file. Space allocated with posixfallocate()  may  be
     freed by a successful call to ftruncate(3C) that reduces the
     file size to a size smaller than offset]len.

RETURN VALUES
     Upon successful completion, posixfallocate() returns  zero.
     Otherwise,  an  error  number  is  returned  to indicate the
     error.

ERORS
     The posixfallocate() function will fail if:

     EBADF     The fd argument is not a valid file descriptor  or
               references  a  file  that was opened without write
               permission.


     EFBIG     The value of offset]len is greater than  the  max-
               imum file size.


     EINTR     A signal was caught during execution.


     EINVAL    The len argument is less than or equal to zero, or
               the  offset  argument  is  less  than zero, or the



SunOS 5.11          Last change: 14 Jul 2008                    1






Standard C Library Functions                  posixfallocate(3C)



               underlying  file  system  does  not  support  this
               operation.


     EIO       An I/O error occurred while reading from or  writ-
               ing to a file system.


     ENODEV    The fd argument does not refer to a regular file.


     ENOSPC    There is insufficient free space remaining on  the
               file system storage media.


     ESPIPE    The fd argument is associated with a pipe or FIFO.


USAGE
     The posixfallocate() function has a transitional  interface
     for 64-bit file offsets. See lf64(5).

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    
     MT-Level                     MT-Safe                     
    
     Standard                     See standards(5).           
    


SEE ALSO
     creat(2), open(2), unlink(2), ftruncate(3C),  attributes(5),
     standards(5)













SunOS 5.11          Last change: 14 Jul 2008                    2