Janet 1.16.1-87f8fe1 Documentation
(Other Versions:
1.15.0
1.13.1
1.12.2
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1.10.1
1.9.1
1.8.1
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1.6.0
1.5.1
1.5.0
1.4.0
1.3.1
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File Module
Index
file/close file/flush file/open file/popen file/read file/seek file/temp file/write
file/close cfunction
(file/close f) Close a file and release all related resources. When you are done reading a file, close it to prevent a resource leak and let other processes read the file. If the file is the result of a file/popen call, close waits for and returns the process exit status.Community Examples
file/flush cfunction
(file/flush f) Flush any buffered bytes to the file system. In most files, writes are buffered for efficiency reasons. Returns the file handle.Community Examples
file/open cfunction
(file/open path &opt mode) Open a file. `path` is an absolute or relative path, and `mode` is a set of flags indicating the mode to open the file in. `mode` is a keyword where each character represents a flag. If the file cannot be opened, returns nil, otherwise returns the new file handle. Mode flags: * r - allow reading from the file * w - allow writing to the file * a - append to the file Following one of the initial flags, 0 or more of the following flags can be appended: * b - open the file in binary mode (rather than text mode) * + - append to the file instead of overwriting it * n - error if the file cannot be opened instead of returning nilCommunity Examples
file/popen cfunction
(file/popen command &opt mode) (DEPRECATED for os/spawn) Open a file that is backed by a process. The file must be opened in either the :r (read) or the :w (write) mode. In :r mode, the stdout of the process can be read from the file. In :w mode, the stdin of the process can be written to. Returns the new file.Community Examples
file/read cfunction
(file/read f what &opt buf) Read a number of bytes from a file `f` into a buffer. A buffer `buf` can be provided as an optional third argument, otherwise a new buffer is created. `what` can either be an integer or a keyword. Returns the buffer with file contents. Values for `what`: * :all - read the whole file * :line - read up to and including the next newline character * n (integer) - read up to n bytes from the fileCommunity Examples
file/seek cfunction
(file/seek f &opt whence n) Jump to a relative location in the file `f`. `whence` must be one of: * :cur - jump relative to the current file location * :set - jump relative to the beginning of the file * :end - jump relative to the end of the file By default, `whence` is :cur. Optionally a value `n` may be passed for the relative number of bytes to seek in the file. `n` may be a real number to handle large files of more than 4GB. Returns the file handle.Community Examples
file/temp cfunction
(file/temp) Open an anonymous temporary file that is removed on close. Raises an error on failure.Community Examples
file/write cfunction
(file/write f bytes) Writes to a file. 'bytes' must be string, buffer, or symbol. Returns the file.Community Examples