processx_connections: Processx connections

Description Usage Arguments Details

Description

These functions are currently experimental and will change in the future. Note that processx connections are not compatible with R's built-in connection system.

Usage

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conn_create_fd(fd, encoding = "", close = TRUE)

conn_create_pipepair(encoding = "")

conn_read_chars(con, n = -1)

## S3 method for class 'processx_connection'
conn_read_chars(con, n = -1)

conn_read_lines(con, n = -1)

## S3 method for class 'processx_connection'
conn_read_lines(con, n = -1)

conn_is_incomplete(con)

## S3 method for class 'processx_connection'
conn_is_incomplete(con)

conn_write(con, str, sep = "\n", encoding = "")

## S3 method for class 'processx_connection'
conn_write(con, str, sep = "\n",
  encoding = "")

conn_create_file(filename, read = NULL, write = NULL)

conn_set_stdout(con, drop = TRUE)

conn_set_stderr(con, drop = TRUE)

conn_get_fileno(con)

conn_disable_inheritance()

Arguments

fd

Integer scalar, a Unix file descriptor.

encoding

Encoding of the readable connection when reading.

close

Whether to close the OS file descriptor when closing the connection. Sometimes you want to leave it open, and use it again in a conn_create_fd call. Encoding to re-encode str into when writing.

con

Processx connection object.

n

Number of characters or lines to read. -1 means all available characters or lines.

str

Character or raw vector to write.

sep

Separator to use if str is a character vector. Ignored if str is a raw vector.

filename

File name.

read

Whether the connection is readable.

write

Whethe the connection is writeable.

drop

Whether to close the original stdout/stderr, or keep it open and return a connection to it.

Details

conn_create_fd() creates a connection from a file descriptor.

conn_create_pipepair() creates a pair of connected connections, the first one is writeable, the second one is readable.

conn_read_chars() reads UTF-8 characters from the connections. If the connection itself is not UTF-8 encoded, it re-encodes it.

conn_read_lines() reads lines from a connection.

conn_is_incomplete() returns FALSE if the connection surely has no more data.

conn_write() writes a character or raw vector to the connection. It might not be able to write all bytes into the connection, in which case it returns the leftover bytes in a raw vector. Call conn_write() again with this raw vector.

conn_create_file() creates a connection to a file.

conn_set_stdout() set the standard output of the R process, to the specified connection.

conn_set_stderr() set the standard error of the R process, to the specified connection.

conn_get_fileno() return the integer file desciptor that belongs to the connection.

conn_disable_inheritance() can be called to disable the inheritance of all open handles. Call this function as soon as possible in a new process to avoid inheriting the inherited handles even further. The function is best effort to close the handles, it might still leave some handles open. It should work for stdin, stdout and stderr, at least.


r-pkgs/processx documentation built on Oct. 7, 2018, 9:09 a.m.