pSOSystem System Calls - Read

pHILE+ System Calls ftruncate_f
ftruncate_f Changes the size of a file specified by its file identifier.
#include
unsigned long ftruncate_f(
unsigned long fid, /* file identifier */
unsigned long length /* file size in bytes */
)
Volume Types
Description
Arguments
Return Value
pHILE+, MS-DOS, and NFS formatted volumes.
ftruncate_f() functions the same as truncate_f() except that
ftruncate_f() changes the size of a file by using the file identifier instead of the
pathname. The file identifier is first obtained with either open_f() or open_fn().
Unlike annex_f(), this system call changes both the logical and the physical file
size. (annex_f() changes only the physical file size.)
On pHILE+ or MS-DOS volumes, the file must have been opened only once, that is
no other task has it open and the calling task has opened it only once. If this is
violated, the error E_FOPEN is returned.
On pHILE+ or MS-DOS volumes, if the file is truncated shorter than its L_ptr, the
L_ptr is changed to the new end-of-file.
fid Specifies the file identifier associated with the file.
length Specifies the new file size. If the file was previously longer than
length, the extra bytes are truncated. If it was shorter, the bytes
between the old and new lengths are filled with 0’s.
This system call returns 0 on success or an error code on failure.
pSOSystem System Calls 2-43
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