io_open()

Initialize an IO stream

Synopsis:

#include <img/img.h>

io_stream_t *io_open( io_open_f *open_f,
                      io_mode_t  mode, ...)

Arguments:

open_f
A pointer to a function to establish a stream. There are two functions supplied by the library: IO_FD (for fd-based reading/writing) and IO_MEM (for memory buffer based reading/writing). See below.
mode
The open mode, either IO_READ or IO_WRITE.
...
Additional parameters depending on the open_f specified, described below.

Library:

libimg

Use the -l img option to qcc to link against this library.

Description:

This function initializes a stream. The stream can be a fd-based, or a memory buffer, depending on the open_f specified:

IO_FD
Buffered streaming for unix-type fd's. An additional parmameter is required: an int specifying the (previously opened) fd that is ready for reading or writing.
IO_MEM
Streaming support for a memory buffer. Additional parameters are required (in order):
  1. an unsigned to specify size of the memory buffer. This must be non-zero.
  2. a void pointer to specify the address of the buffer.

When your application is finished with a stream, it should call io_close() to release it.

Returns:

A pointer to the stream object, or NULL if an error occurred (errno is set).

Errors:

ENOMEM
Insufficient memory to allocate structures.
EINVAL
Invalid open_f or mode.
ENOTSUP
Mode not supported for stream.

Classification:

Image library

Safety:
Interrupt handler No
Signal handler No
Thread No