modem_script()

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Прототип:

#include <sys/modem.h>
                                       
int modem_script( int fd,
                  struct modem_script *table,
                  speed_t *baud,
                  void (*io)( char *progress,
                              char *in,
                              char *out ),
                  int (*cancel)(void) );

Аргументы:

fd

The file descriptor for the device that you want to read from; see modem_open().

table

An array of struct modem_script that comprise a script of commands that you want to run on the device.

baud

A pointer to a speed_t where the function can store the baud rate (if you script says to do so).

io

A function that's called to process each string that's emitted or received.

cancel

NULL, or a callback function that's called whenever the newquiet time period (specified in the script) expires while waiting for input.

Библиотека:

libc

Описание:

The modem_script() function runs the script table on the device associated with the file descriptor fd. The script implements a simple state machine that emits strings and waits for responses.

Each string that's emitted or received is passed to the function io() as follows:

This lets an application set up a callback that can display the script's interaction in a status window.

If you provide a cancel function, it's called once each newquiet 1/10 of a second while waiting for input. If this function returns a nonzero value, the read returns immediately with -1 and errno is set to ETIMEDOUT. You can use the cancel function as a callback in a graphical dialer that needs to support a cancel button to stop a script.

The table is an array of struct modem_script.

When this script is passed to modem_script(), the current state is set to 1, and the output is ATZ (the response in the first array element).

While in any state, modem_script() waits for input, matching it against the current state or the wildcard state of 0.

State 1

State 2

State 3

State 4

State 5

If you set the flag MODEM_BAUD for a state, then any number embedded in a matching response is extracted and assigned as a number to the baud parameter.

If you don't set the flag MODEM_NOECHO for a state, then all emitted strings are also given to the passed io function as (*io)(0, 0, response).

Возвращаемое значение:

≠-1

The retvalue member of a script entry that terminates the script. This will always be a positive number.

-1

Возникла ошибка. Код ошибки записан в errno.

Коды ошибок:

EAGAIN

The O_NONBLOCK flag is set for the file descriptor, and the process would be delayed in the write operation.

EBADF

The file descriptor, fildes, isn't a valid file descriptor open for writing.

EINTR

The write operation was interrupted by a signal, and either no data was transferred, or the resource manager responsible for that file doesn't report partial transfers.

EIO

A physical I/O error occurred. The precise meaning depends on the device.

EPIPE

An attempt was made to write to a pipe (or FIFO) that isn't open for reading by any process. A SIGPIPE signal is also sent to the process.

Классификация:

ЗОСРВ «Нейтрино»

Точка остановки потока

Да

Обработчик прерываний

Нет

Обработчик сигналов

Смотри ниже

В потоке

Смотри ниже

Предостережения:

Depending on what you do in your cancel function, it might or might not be safe to call modem_script() from a signal handler or a multithreaded program.

Тематические ссылки:

struct modem_script, modem_open(), modem_read(), modem_write()

Предыдущий раздел: Описание API системной библиотеки