vera:io

Console I/O and file operations.

import "vera:io"

Overview

Provides console I/O and file operations. All functions are built on compiler primitives (__vera_sys_*) which the compiler maps to platform-specific syscalls.

Dependencies: None (uses primitives directly)

Constants

File Open Flags

Combine with bitwise_or when calling open_file:

Seek Origins

Functions

Console I/O

write_stdout

function write_stdout(data: ptr, length: i64) -> i64

Write bytes to standard output (fd 1).

Parameters:

• data (ptr) — pointer to the byte buffer to write
• length (i64) — number of bytes to write

Returns: number of bytes actually written

write_stderr

function write_stderr(data: ptr, length: i64) -> i64

Write bytes to standard error (fd 2).

Parameters:

• data (ptr) — pointer to the byte buffer to write
• length (i64) — number of bytes to write

Returns: number of bytes actually written

read_stdin

function read_stdin(buffer: ptr, max_length: i64) -> i64

Read bytes from standard input (fd 0).

Parameters:

• buffer (ptr) — pointer to the buffer to read into
• max_length (i64) — maximum number of bytes to read

Returns: number of bytes actually read

File Operations

open_file

function open_file(path: ptr, flags: i32) -> i32

Open a file with the specified flags. The path must be a null-terminated string. Uses default file permissions 0644 (owner read/write, group/other read).

Parameters:

• path (ptr) — null-terminated file path
• flags (i32) — combination of file open flags (see Constants above)

Returns: file descriptor on success, or a negative value on error

create_file

function create_file(path: ptr) -> i32

Create a new file (or truncate an existing one) for writing. Equivalent to opening with FILE_WRITE | FILE_CREATE | FILE_TRUNCATE (flags = 14). The path must be null-terminated.

Parameters:

• path (ptr) — null-terminated file path

Returns: file descriptor on success, or a negative value on error

close_file

function close_file(fd: i32) -> i32

Close an open file descriptor.

Parameters:

• fd (i32) — file descriptor to close

Returns: 0 on success, or a negative value on error

write_file

function write_file(fd: i32, data: ptr, length: i64) -> i64

Write bytes to an open file.

Parameters:

• fd (i32) — file descriptor
• data (ptr) — pointer to the byte buffer to write
• length (i64) — number of bytes to write

Returns: number of bytes actually written

read_file

function read_file(fd: i32, buffer: ptr, max_length: i64) -> i64

Read bytes from an open file into a buffer.

Parameters:

• fd (i32) — file descriptor
• buffer (ptr) — pointer to the buffer to read into
• max_length (i64) — maximum number of bytes to read

Returns: number of bytes actually read

delete_file

function delete_file(path: ptr) -> i32

Delete a file from the filesystem. The path must be null-terminated.

Parameters:

• path (ptr) — null-terminated file path

Returns: 0 on success, or a negative value on error

rename_file

function rename_file(old_path: ptr, new_path: ptr) -> i32

Rename or move a file. Both paths must be null-terminated.

Parameters:

• old_path (ptr) — null-terminated current file path
• new_path (ptr) — null-terminated new file path

Returns: 0 on success, or a negative value on error

file_size

function file_size(path: ptr) -> i64

Get the size of a file in bytes. The path must be null-terminated.

Parameters:

• path (ptr) — null-terminated file path

Returns: file size in bytes, or a negative value on error

seek_file

function seek_file(fd: i32, offset: i64, origin: i32) -> i64

Reposition the read/write offset of an open file.

Parameters:

• fd (i32) — file descriptor
• offset (i64) — byte offset relative to origin
• origin (i32) — seek origin: 0 = from start, 1 = from current position, 2 = from end

Returns: the new absolute position in the file, or a negative value on error