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28 .\" @(#)truncate.2 8.1 (Berkeley) 6/4/93
37 .Nd truncate or extend a file to a specified length
43 .Fn truncate "const char *path" "off_t length"
45 .Fn ftruncate "int fd" "off_t length"
50 causes the file named by
54 to be truncated or extended to
58 was larger than this size, the extra data
60 If the file was smaller than this size,
61 it will be extended as if by writing bytes
66 system call causes the file or shared memory object backing the file descriptor
68 to be truncated or extended to
71 The file descriptor must be a valid file descriptor open for writing.
72 The file position pointer associated with the file descriptor
77 If the file to be modified is not a directory or
80 call has no effect and returns the value 0.
88 A component of the path prefix is not a directory.
89 .It Bq Er ENAMETOOLONG
90 A component of a pathname exceeded 255 characters,
91 or an entire path name exceeded 1023 characters.
93 The named file does not exist.
95 Search permission is denied for a component of the path prefix.
97 The named file is not writable by the user.
99 Too many symbolic links were encountered in translating the pathname.
101 The named file has its immutable or append-only flag set, see the
103 manual page for more information.
105 The named file is a directory.
107 The named file resides on a read-only file system.
109 The file is a pure procedure (shared text) file that is being executed.
113 argument was greater than the maximum file size.
117 argument was less than 0.
119 An I/O error occurred updating the inode.
121 Corrupted data was detected while reading from the file system.
126 points outside the process's allocated address space.
138 is not a valid descriptor.
143 references a file descriptor that is not a regular file or shared memory object.
148 is not open for writing.
159 system calls appeared in
162 These calls should be generalized to allow ranges
163 of bytes in a file to be discarded.
165 Historically, the use of
169 to extend a file was not portable, but this behavior became required in