### Struct

# GLib Scanner

since: 2.0

#### Description

    struct GScanner {
      gpointer user_data;
      guint max_parse_errors;
      guint parse_errors;
      const gchar* input_name;
      GData* qdata;
      GScannerConfig* config;
      GTokenType token;
      GTokenValue value;
      guint line;
      guint position;
      GTokenType next_token;
      GTokenValue next_value;
      guint next_line;
      guint next_position;
      GScannerMsgFunc msg_handler;
    }

`GScanner` provides a general-purpose lexical scanner.

You should set `input_name` after creating the scanner, since it is used by the default message handler when displaying warnings and errors. If you are scanning a file, the filename would be a good choice.

The `user_data` and `max_parse_errors` fields are not used. If you need to associate extra data with the scanner you can place them here.

If you want to use your own message handler you can set the `msg_handler` field. The type of the message handler function is declared by `GScannerMsgFunc`.

###### Structure members

`user_data`

  Unused.

`max_parse_errors`

  Unused.

`parse_errors`

  G_scanner_error() increments this field.

`input_name`

  Name of input stream, featured by the default message handler.

`qdata`

  Quarked data.

`config`

  Link into the scanner configuration.

`token`

  Token parsed by the last `g_scanner_get_next_token()`

`value`

  Value of the last token from `g_scanner_get_next_token()`

`line`

  Line number of the last token from `g_scanner_get_next_token()`

`position`

  Char number of the last token from `g_scanner_get_next_token()`

`next_token`

  Token parsed by the last `g_scanner_peek_next_token()`

`next_value`

  Value of the last token from `g_scanner_peek_next_token()`

`next_line`

  Line number of the last token from `g_scanner_peek_next_token()`

`next_position`

  Char number of the last token from `g_scanner_peek_next_token()`

`msg_handler`

  Handler function for _warn and _error.

Available since: 2.0

#### Functions

###### g_scanner_new

Creates a new `GScanner`.

since: 2.0

#### Instance methods

###### g_scanner_cur_line

Returns the current line in the input stream (counting from 1). This is the line of the last token parsed via g_scanner_get_next_token().

since: 2.0

###### g_scanner_cur_position

Returns the current position in the current line (counting from 0). This is the position of the last token parsed via g_scanner_get_next_token().

since: 2.0

###### g_scanner_cur_token

Gets the current token type. This is simply the `token` field in the `GScanner` structure.

since: 2.0

###### g_scanner_cur_value

Gets the current token value. This is simply the `value` field in the `GScanner` structure.

since: 2.0

###### g_scanner_destroy

Frees all memory used by the `GScanner`.

since: 2.0

###### g_scanner_eof

Returns `TRUE` if the scanner has reached the end of the file or text buffer.

since: 2.0

###### g_scanner_error

Outputs an error message, via the `GScanner` message handler.

since: 2.0

###### g_scanner_get_next_token

Parses the next token just like `g_scanner_peek_next_token()` and also removes it from the input stream. The token data is placed in the `token`, `value`, `line`, and `position` fields of the `GScanner` structure.

since: 2.0

###### g_scanner_input_file

Prepares to scan a file.

since: 2.0

###### g_scanner_input_text

Prepares to scan a text buffer.

since: 2.0

###### g_scanner_lookup_symbol

Looks up a symbol in the current scope and return its value. If the symbol is not bound in the current scope, `NULL` is returned.

since: 2.0

###### g_scanner_peek_next_token

Parses the next token, without removing it from the input stream. The token data is placed in the `next_token`, `next_value`, `next_line`, and `next_position` fields of the `GScanner` structure.

since: 2.0

###### g_scanner_scope_add_symbol

Adds a symbol to the given scope.

since: 2.0

###### g_scanner_scope_foreach_symbol

Calls the given function for each of the symbol/value pairs in the given scope of the `GScanner`. The function is passed the symbol and value of each pair, and the given `user_data` parameter.

since: 2.0

###### g_scanner_scope_lookup_symbol

Looks up a symbol in a scope and return its value. If the symbol is not bound in the scope, `NULL` is returned.

since: 2.0

###### g_scanner_scope_remove_symbol

Removes a symbol from a scope.

since: 2.0

###### g_scanner_set_scope

Sets the current scope.

since: 2.0

###### g_scanner_sync_file_offset

Rewinds the filedescriptor to the current buffer position and blows the file read ahead buffer. This is useful for third party uses of the scanners filedescriptor, which hooks onto the current scanning position.

since: 2.0

###### g_scanner_unexp_token

Outputs a message through the scanner’s msg_handler, resulting from an unexpected token in the input stream. Note that you should not call `g_scanner_peek_next_token()` followed by `g_scanner_unexp_token()` without an intermediate call to g_scanner_get_next_token(), as `g_scanner_unexp_token()` evaluates the scanner’s current token (not the peeked token) to construct part of the message.

since: 2.0

###### g_scanner_warn

Outputs a warning message, via the `GScanner` message handler.

since: 2.0