X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=doc%2Fusage.html;h=a71b855221b5643a9fd96d5fbd29b8835e163748;hb=e64a3ac05141381579c407b779d6db66ecdb367d;hp=3d13ab0d8f93eedabbd68c4f3fdb7deb04af6e8c;hpb=a6f453d612fe285d2585b689e3e4d675de455510;p=gedcom-parse.git diff --git a/doc/usage.html b/doc/usage.html index 3d13ab0..a71b855 100644 --- a/doc/usage.html +++ b/doc/usage.html @@ -1,399 +1,792 @@ - - -
-libgedcom.so
), to be linked in the application
- programgedcom.h
), to be used in the sources
-of the application program$PREFIX/share/gedcom-parse
- that contains some additional stuff, but which is not immediately important
- at first. I'll leave the description of the data directory for later.libgedcom.so
), to be linked in the
+application program, which implements the callback parsergedcom.h
), to be used in the sources
+ of the application programgedcom-tags.h
) that is also installed,
+ but that is automatically included via gedcom.h
libgedcom.so
is also needed in this case, because the object model uses the callback parser internally):libgedcom_gom.so
), to be linked in the application program, which implements the C object modelgom.h
), to be used in the sources of the application program$PREFIX/share/gedcom-parse
+ that contains some additional stuff, but which is not immediately
+ important at first. I'll leave the description of the data directory
+ for later.gedcom.h
header is assumed, as everywhere
+in this manual):int result;
...
- result = gedcom_parse_file("myfamily.ged");
-
- Although this will not provide much information, one thing it does is parse
-the entire file and return the result. The function returns 0 on success
-and 1 on failure. No other information is available using this function
-only.- In the above piece of code,void my_message_handler (Gedcom_msg_type type, -char *msg)
- {
- ...
- }
- ...
- gedcom_set_message_handler(my_message_handler);
- ...
- result = gedcom_parse_file("myfamily.ged");
-
my_message_handler
is the callback
-that will be called for errors (type=ERROR
), warnings (
-type=WARNING
) and messages (type=MESSAGE
). The callback
-must have the signature as in the example. For errors, the
-msg
passed to the callback will have the format:- Note that the entire string will be properly internationalized, and encoded -in UTF-8 (see "Why UTF-8?" LINK TBD). Also, no newline -is appended, so that the application program can use it in any way it wants. - Warnings are similar, but use "Warning" instead of "Error". Messages -are plain text, without any prefix.Error on line
<lineno>: <actual_message>
-
printf
- is used in the message handler.- Using theGedcom_ctxt my_header_start_cb (int level, -Gedcom_val xref, char *tag)
- {
- printf("The header starts\n");
- return (Gedcom_ctxt)1;
- }
-
- void my_header_end_cb (Gedcom_ctxt self)
- {
- printf("The header ends, context is %d\n", self); /* context -will print as "1" */
- }
-
- ...
- gedcom_subscribe_to_record(REC_HEAD, my_header_start_cb, -my_header_end_cb);
- ...
- result = gedcom_parse_file("myfamily.ged");
-
gedcom_subscribe_to_record
function, the application
-requests to use the specified callbacks as start and end callback. The end
-callback is optional: you can pass NULL
if you are not interested
-in the end callback. The identifiers to use as first argument to the
-function (here REC_HEAD
) are described in the
-interface details.Gedcom_ctxt
type that is used as a result of the start
-callback and as an argument to the end callback is vital for passing context
-necessary for the application. This type is meant to be opaque; in
-fact, it's a void pointer, so you can pass anything via it. The important
-thing to know is that the context that the application returns in the start
-callback will be passed in the end callback as an argument, and as we will
-see shortly, also to all the directly subordinate elements of the record.struct
that will contain the information for the
-header. In the end callback, the application could then e.g. do some
-finalizing operations on the struct
to put it in its database.Gedcom_val
type for the xref
argument
-was not discussed, see further for this)- The subscription mechanism for elements is similar, only the signatures -of the callbacks differ. The signature for the start callback shows -that the context of the parent line (e.g. theGedcom_ctxt my_header_source_start_cb(Gedcom_ctxt -parent,
- - int - level,
- - char* - tag,
- - char* - raw_value,
- - Gedcom_val parsed_value)
- {
- char *source = GEDCOM_STRING(parsed_value);
- printf("This file was written by %s\n", source);
- return parent;
- }
-
- void my_header_source_end_cb(Gedcom_ctxt parent,
- - Gedcom_ctxt self,
- - Gedcom_val parsed_value)
- {
- printf("End of the source description\n");
- }
-
- ...
- gedcom_subscribe_to_element(ELT_HEAD_SOUR,
- - my_header_source_start_cb,
- - my_header_source_end_cb);
- ...
- result = gedcom_parse_file("myfamily.ged");
-
struct
that describes
-the header) is passed to this start callback. The callback itself returns
-here the same context, but this can be its own context object of course. The
-end callback is called with both the context of the parent and the context
-of itself, which will be the same in the example. Again, the list of
-identifiers to use as a first argument for the subscription function are
-detailed in the interface details
-.Gedcom_val
type is meant to be an opaque type. The
-only thing that needs to be known about it is that it can contain specific
-data types, which have to be retrieved from it using pre-defined macros. These
-data types are described in the
-interface details. gedcom.h
and gom.h
is required):int result;
+ ...
+ gedcom_init();
+ ...
+ result = gom_parse_file("myfamily.ged");
+
+The call to gom_parse_file
will build the C object model, which is then a complete representation of the GEDCOM file.gedcom_init
() should be one of the first calls
+in your program. The requirement is that it should come before the first
+call to iconv_open
(part of the generic character set conversion
+feature) in the program, either by your program itself, or indirectly by
+the library calls it makes. Practically, it should e.g. come before
+ any calls to any GTK functions, because GTK uses iconv_open
+ in its initialization.-lgedcom
option
+on the linking of the program as the last option, so that its initialization
+code is run first. In the case of using the C object model, the linking
+options should be: -lgedcom_gom -lgedcom
gedcom_init()
also initializes locale handling by calling setlocale(LC_ALL, "")
, in case the application would not do this (it doesn't hurt for the application to do the same).Gedcom_val
argument of the end callback
-is currently not used. It is there for future enhancements.Gedcom_val
argument in the
-start callback for records. This argument is currently a string value
-giving the pointer in string form.void my_default_cb (Gedcom_ctxt parent, -int level, char* tag, char* raw_value)
-{
- ...
-}
-
-...
- gedcom_set_default_callback(my_default_cb);
-...
-result = gedcom_parse_file("myfamily.ged");
+ A typical piece of code would be (gom_parse_file
would be called in case the C object model is used):
+ +- This callback has a similar signature as the previous ones, but -it doesn't contain a parsed value. However, it does contain the parent -context, that was returned by the application for the most specific containing -tag that the application supported.void my_message_handler (Gedcom_msg_type type, + char *msg)
+ {
+ ...
+ }
+ ...
+ gedcom_set_message_handler(my_message_handler);
+ ...
+ result = gedcom_parse_file("myfamily.ged");
-
-Suppose e.g. that this callback is called for some tags in the header that -are specific to some other application, then our application could make sure -that the parent context contains the struct or object that represents the -header, and use the default callback here to add the level, tag and raw_value -as plain text in a member of that struct or object, thus preserving the information. - The application can then write this out when the data is saved again -in a GEDCOM file. To make it more specific, consider the following -example:
--Note that the default callback will be called for any tag that isn't specifically -subscribed upon by the application, and can thus be called in various contexts. - For simplicity, the example above doesn't take this into account (the -struct header {
- char* source;
- ...
- char* extra_text;
-};
+ In the above piece of code,my_message_handler
is the + callback that will be called for errors (type=ERROR
), warnings + (type=WARNING
) and messages (type=MESSAGE
). The + callback must have the signature as in the example. For errors, +themsg
passed to the callback will have the format:
+ ++ Note that the entire string will be properly internationalized, and + encoded in UTF-8 (Why UTF-8?). Also, +no newline is appended, so that the application program can use it in any +way it wants. Warnings are similar, but use "Warning" instead of "Error". + Messages are plain text, without any prefix.Error on line
<lineno>: <actual_message>
+
-Gedcom_ctxt my_header_start_cb(int level, Gedcom_val xref, char* tag)
-{
- struct header head = my_make_header_struct();
- return (Gedcom_ctxt)head;
-}
+ With this in place, the resulting code will already show errors and + warnings produced by the parser, e.g. on the terminal if a simple+ printf
is used in the message handler.
+ +
+Data callback mechanism
+ The most important use of the parser is of course to get the data +out of the GEDCOM file. This section focuses on the callback mechanism (see here for the C object model). In fact, the mechanism involves two levels.
-void my_default_cb(Gedcom_ctxt parent, int level, char* tag, char* raw_value)
-{
- struct header head = (struct header)parent;
- my_header_add_to_extra_text(head, level, tag, raw_value);
-}
+ The primary level is that each of the sections in a GEDCOM file is + notified to the application code via a "start element" callback and an + "end element" callback (much like in a SAX interface for XML), i.e. when + a line containing a certain tag is parsed, the "start element" callback + is called for that tag, and when all its subordinate lines with their +tags have been processed, the "end element" callback is called for the +original tag. Since GEDCOM is hierarchical, this results in properly +nested calls to appropriate "start element" and "end element" callbacks (note: see compatibility handling).
-gedcom_set_default_callback(my_default_cb);
-gedcom_subscribe_to_record(REC_HEAD, my_header_start, NULL);
-...
-result = gedcom_parse_file(filename);
-parent
could be of different types, depending -on the context).
-
-Other API functions
-Although the above describes the basic interface of libgedcom, there are -some other functions that allow to customize the behaviour of the library. - These will be explained in the current section.
-
-Debugging
-The library can generate various debugging output, not only from itself, -but also the debugging output generated by the yacc parser. By default, -no debugging output is generated, but this can be customized using the following -function:
-void gedcom_set_debug_level (int level, -FILE* trace_output)
+ However, it would be typical for a genealogy program to support only + a subset of the GEDCOM standard, certainly a program that is still under + development. Moreover, under GEDCOM it is allowed for an application + to define its own tags, which will typically not be supported by +another application. Still, in that case, data preservation is important; + it would hardly be accepted that information that is not understood by + a certain program is just removed.
+
+ Therefore, the second level of callbacks involves a "default callback". + An application needs to subscribe to callbacks for tags it does support, + and need to provide a "default callback" which will be called for tags +it doesn't support. The application can then choose to just store +the information that comes via the default callback in plain textual format.
+
+ After this introduction, let's see what the API looks like...
+
+ +Start and end callbacks
+ +Callbacks for records
+ As a simple example, we will get some information from the header +of a GEDCOM file. First, have a look at the following piece of code:
+
+ +-TheGedcom_ctxt my_header_start_cb (Gedcom_rec rec,
+ int level,
+ + Gedcom_val xref,
+ + char *tag,
+ + char *raw_value,
+ + int parsed_tag,
+ + Gedcom_val parsed_value)
+ {
+ printf("The header starts\n");
+ return (Gedcom_ctxt)1;
+ }
+
+ void my_header_end_cb (Gedcom_rec rec, Gedcom_ctxt self)
+ {
+ printf("The header ends, context is %d\n", (int)self); + /* context will print as "1" */
+ }
+
+ ...
+ gedcom_subscribe_to_record(REC_HEAD, my_header_start_cb, + my_header_end_cb);
+ ...
+ result = gedcom_parse_file("myfamily.ged");
level
can be one of the following values:
--
-If the- 0: no debugging information (this is the default)
-- 1: only debugging information from libgedcom -itself
-- 2: debugging information from libgedcom and yacc
-trace_output
isNULL
, debugging information -will be written tostderr
, otherwise the given file handle is -used (which must be open).
+ Using thegedcom_subscribe_to_record
function, the + application requests to use the specified callbacks as start and end +callback. The end callback is optional: you can passNULL
+ if you are not interested in the end callback. The identifiers +to use as first argument to the function (hereREC_HEAD
) +are described in the interface +details . These are also passed as first argument in the callbacks (theGedcom_rec
argument).
+
+ From the name of the function it becomes clear that this function +is specific to complete records. For the separate elements in records + there is another function, which we'll see shortly. Again, the callbacks + need to have the signatures as shown in the example.
-Error treatment
-One of the previous sections already described the callback to be registered -to get error messages. The library also allows to customize what happens -on an error, using the following function:
-void gedcom_set_error_handling (Gedcom_err_mech -mechanism)
+ TheGedcom_ctxt
type that is used as a result of the +start callback and as an argument to the end callback is vital for passing +context necessary for the application. This type is meant to be opaque; +in fact, it's a void pointer, so you can pass anything via it. The +important thing to know is that the context that the application returns +in the start callback will be passed in the end callback as an argument, +and as we will see shortly, also to all the directly subordinate elements +of the record.
+
+ Thetag
is the GEDCOM tag in string format, theparsed_tag
+ is an integer, for which symbolic values are defined asTAG_HEAD,
+TAG_SOUR,
TAG_DATA,
... andUSERTAG +
for the application-specific tags. These values +are defined in the header
gedcom-tags.h
that is installed, +and included viagedcom.h
(so no need to includegedcom-tags.h
+ yourself).
+
+ The example passes a simple integer as context, but an application + could e.g. pass astruct
(or an object in a C++ application) + that will contain the information for the header. In the end callback, + the application could then e.g. do some finalizing operations on the +struct
to put it in its database.
+
+ (Note that theGedcom_val
type for thexref
+ andparsed_value
arguments was not discussed, see further + for this)
+
+ +Callbacks for elements
+ We will now retrieve the SOUR field (the name of the program that +wrote the file) from the header:
+ +-TheGedcom_ctxt my_header_source_start_cb(Gedcom_elt elt,
+ + Gedcom_ctxt + parent,
+ + int + level,
+ + char* + tag,
+ + char* + raw_value,
+ + int + parsed_tag,
+ + Gedcom_val + parsed_value)
+ {
+ char *source = GEDCOM_STRING(parsed_value);
+ printf("This file was written by %s\n", source);
+ return parent;
+ }
+
+ void my_header_source_end_cb(Gedcom_elt elt,
+ Gedcom_ctxt parent,
+ + Gedcom_ctxt self,
+ + Gedcom_val parsed_value)
+ {
+ printf("End of the source description\n");
+ }
+
+ ...
+ gedcom_subscribe_to_element(ELT_HEAD_SOUR,
+ + my_header_source_start_cb,
+ + my_header_source_end_cb);
+ ...
+ result = gedcom_parse_file("myfamily.ged");
mechanism
can be one of:
--
-This doesn't influence the generation of error or warning messages, only -the behaviour of the parser and its return code.- -
IMMED_FAIL
: immediately fail the parsing -on an error (this is the default)- -
DEFER_FAIL
: continue parsing after an -error, but return a failure code eventually- -
IGNORE_ERRORS
: continue parsing after -an error, return success always
+ The subscription mechanism for elements is similar, only the signatures + of the callbacks differ. The signature for the start callback shows + that the context of the parent line (here e.g. thestruct
+ that describes the header) is passed to this start callback. The + callback itself returns here in this example the same context, but this +can be its own context object of course. The end callback is called +with both the context of the parent and the context of itself, which in this +example will be the same. Again, the list of identifiers to use as +a first argument for the subscription function are detailed in the interface details . Again, these are passed as first argument in the callback (theGedcom_elt
argument).
+
+ If we look at the other arguments of the start callback, we see the + level number (the initial number of the line in the GEDCOM file), the tag + (e.g. "SOUR"), and then a raw value, a parsed tag and a parsed value. The + raw value is just the raw string that occurs as value on the line next +to the tag (in UTF-8 encoding). The parsed value is the meaningful +value that is parsed from that raw string. The parsed tag is described +in the section for record callbacks above.
-Compatibility mode
+ TheGedcom_val
type is meant to be an opaque type. The + only thing that needs to be known about it is that it can contain specific + data types, which have to be retrieved from it using pre-defined macros. + These data types are described in the interface details. +
+
+ Some extra notes:
+ + ++
+ + +- The
+Gedcom_val
argument of the end callback + is used to pass 'complete' values, e.g. the full text of a note. See + the interface details + for the exact type of this argument.- There are also two
+ + +Gedcom_val
arguments + in the start callback for records. The first one (xref
+ ) contains thexref_value
corresponding to the cross-reference + (orNULL
if there isn't one), the second one (parsed_value
+ ) contains the value that is parsed from theraw_value
. See + the interface details + .Default callbacks
-Applications are not necessarily true to the GEDCOM spec (or use a different -version than 5.5). The intention is that the library is resilient to -this, and goes in compatibility mode for files written by specific programs -(detected via the HEAD.SOUR tag). This compatibility mode can be enabled -and disabled via the following function:
--The argument can be:void gedcom_set_compat_handling - (int enable_compat)
-
--
-Note that, currently, no actual compatibility code is present, but this is -on the to-do list.- 0: disable compatibility mode
-- 1: allow compatibility mode (this is the default)
-
-
-
$Id: usage.html,v 1.1 2001/12/30 -22:45:43 verthezp Exp $
- $Name$
+ As described above, an application doesn't always implement the entire + GEDCOM spec, and application-specific tags may have been added by other + applications. To preserve this extra data anyway, a default callback + can be registered by the application, as in the following example:
+ ++ This callback has a similar signature as the previous ones, + but it doesn't contain a parsed value. However, it does contain the + parent context, that was returned by the application for the most specific + containing tag that the application supported.void my_default_cb (Gedcom_elt elt, Gedcom_ctxt parent, int level, + char* tag, char* raw_value, int parsed_tag)
+ {
+ ...
+ }
+
+ ...
+ gedcom_set_default_callback(my_default_cb);
+ ...
+ result = gedcom_parse_file("myfamily.ged");
+
+
+ Suppose e.g. that this callback is called for some tags in the header + that are specific to some other application, then our application could + make sure that the parent context contains the struct or object that represents + the header, and use the default callback here to add the level, tag and + raw_value as plain text in a member of that struct or object, thus preserving + the information. The application can then write this out when the +data is saved again in a GEDCOM file. To make it more specific, consider + the following example:
+ ++ Note that the default callback will be called for any tag that isn't + specifically subscribed upon by the application, and can thus be called + in various contexts. For simplicity, the example above doesn't take + this into account (thestruct header {
+ char* source;
+ ...
+ char* extra_text;
+ };
+
+ Gedcom_ctxt my_header_start_cb(Gedcom_rec rec, int level, Gedcom_val xref, char* tag, + char *raw_value,
+ + int parsed_tag, Gedcom_val parsed_value)
+ {
+ struct header head = my_make_header_struct();
+ return (Gedcom_ctxt)head;
+ }
+
+ void my_default_cb(Gedcom_elt elt, Gedcom_ctxt parent, int level, char* tag, char* +raw_value, int parsed_tag)
+ {
+ struct header head = (struct header)parent;
+ my_header_add_to_extra_text(head, level, tag, raw_value);
+ }
+
+ gedcom_set_default_callback(my_default_cb);
+ gedcom_subscribe_to_record(REC_HEAD, my_header_start, NULL);
+ ...
+ result = gedcom_parse_file(filename);
+parent
could be of different + types, depending on the context).
+
+ Note also that the default callback is not called when the parent context + isNULL
. This is e.g. the case if none + of the "upper" tags has been subscribed upon.
+ + +
+Support for writing GEDCOM files
+The Gedcom parser library also contains functions to writing GEDCOM files. + Similar as for the parsing itself, there are two interfaces: an interface +which is very basic, and requires you to call a function for each line in +the GEDCOM file, and an interface which just dumps the Gedcom object model +to a file in one shot (if you use the Gedcom object model).
+
+Again, this section focuses on the basic interface, the Gedcom object model interface is described here.
+
+Opening and closing files
+The basic functions for opening and closing Gedcom files for writing are the following:
++
+The functionGedcom_write_hndl gedcom_write_open (const char* filename);
+int gedcom_write_close (Gedcom_write_hndl hndl, int* total_conv_fails);gedcom_write_open
takes a parameter the name of +the file to write, and returns a write handle, which needs to be used in +subsequent functions. It returnsNULL
in case of errors.
+
+The functiongedcom_write_close
takes, next to the write handle, +an integer pointer as parameter. If you pass an actual pointer for +this, the function will write in it the total number of conversion failures; +you can passNULL
if you're not interested. The function returns 0 in case of success, non-zero in case of failure.
+
+Controlling some settings
+Note that by default the file is written in the same encoding as the read file was in. You can change +this by calling the following function before calling
+gedcom_write_open
, i.e. it affects all files that are opened after it is being called:+
+Theint gedcom_write_set_encoding (Enc_from from, const char* charset, Encoding width, Enc_bom bom);
from
parameter indicates how you want the encoding to be set:
++
+When- +
ENC_FROM_FILE
: The same as the read file was in (this is the default).- +
ENC_FROM_SYS
: Not a valid value here, see below forgedcom_write_set_terminator
+- +
ENC_MANUAL
: From the values given in the following parameters.ENC_FROM_FILE
is selected, the other parameters in the function are ignored (they can be passed as 0). WhenENC_MANUAL
is chosen, the meaning of the other parameters is as follows:
+
+The validcharset
values are given in the first column in the filegedcom.enc
in the data directory of gedcom-parse ($PREFIX/share/gedcom-parse
). + The character sets UNICODE, ASCII and ANSEL are always supported (these +are standard for GEDCOM), as well as ANSI (not standard), but there may be +others.
+
+Thewidth
parameter takes one of the following values:
++
++
+The- +
ONE_BYTE
: This should be used for all character sets except UNICODE.- +
TWO_BYTE_HILO
: High-low encoding for UNICODE (i.e. big-endian)- +
TWO_BYTE_LOHI
: Low-high encoding for UNICODE (i.e. little-endian)bom
parameter determines whether a byte-order-mark should +be written in the file in case of UNICODE encoding (usually preferred because +it then clearly indicates the byte ordering). It takes one of the following +values:
++
For both these parameters you can pass 0 for non-UNICODE encodings, +since that corresponds to the correct values (and is ignored anyway). The +function returns 0 in case of success, non-zero in case of error. Note +that you still need to pass the correct charset value for the HEAD.CHAR tag, +otherwise you will get a warning, and the value will be forced to the correct +value.- +
WITHOUT_BOM
- +
WITH_BOM
+
+Further, it is possible to control the kind of line terminator that is used, via the following function (also to be used beforegedcom_write_open
):
+The values for theint gedcom_write_set_line_terminator (Enc_from from, Enc_line_end end);
from
parameter are given above. The valueENC_FROM_SYS
+is valid here, and means that the normal terminator for the current system +is used (the second parameter of the function is then ignored). This +is the default for this setting.
+
+Theend
parameter takes one of the following values:
++
+By default, this is set to the appropriate line terminator on the current +platform, so it only needs to be changed if there is some special reason +for it.- +
END_CR
: only carriage return ("/r") (system value for Macintosh)- +
END_LF
: only line feed ("/n") (system value for Unix, Mac OS X)- +
END_CR_LF
: first carriage return, then line feed ("/r/n") (system value for DOS, Windows)- +
END_LF_CR
: first line feed, then carriage return ("/n/r")
+Writing data
+For actually writing the data, the principle is that every line in the GEDCOM +file to write corresponds to a call to one of the following functions, except +that CONT/CONC lines can be automatically taken care of. Note that +the resulting GEDCOM file should conform to the GEDCOM standard. Several +checks are built in already, and more will follow, to force this. There +is no compatibility mode for writing GEDCOM files (and probably never will be).
+
+
+In general, each of the following functions expect their input in UTF-8 encoding (see also here). If this is not the case, errors will be returned.
+
+Note that for examples of using these functions you can look at the sources for the Gedcom object model (e.g. the functionwrite_header
ingom/header.c
).
+Records
+For writing lines corresponding to records (i.e. on level 0), the following function is available: ++Theint gedcom_write_record_str (Gedcom_write_hndl hndl, Gedcom_rec rec, const char* xrefstr, const char* value);
hndl
parameter is the write handle that was returned bygedcom_write_open
. Therec
parameter is one of the identifiers given in the first column in this table (exceptREC_USER
: see below). Thexrefstr
andval
parameters are respectively the cross-reference key of the record (something like '@FAM01@
'), and the value of the record line, which should beNULL
for some record types, according to the same table.
+Elements
+For writing lines corresponding to elements (inside records, i.e. on a level +bigger than 0), the following functions are available, depending on the data +type: ++int gedcom_write_element_str (Gedcom_write_hndl hndl, Gedcom_elt elt, int parsed_tag,
+ + int parent_rec_or_elt, const char* value);
+int gedcom_write_element_xref (Gedcom_write_hndl hndl, Gedcom_elt elt, int parsed_tag,
+ + int parent_rec_or_elt, const struct xref_value* +value);
+int gedcom_write_element_date (Gedcom_write_hndl hndl, Gedcom_elt elt, int parsed_tag,
+ + int parent_rec_or_elt, const struct date_value* +value);
+i
nt gedcom_write_element_age (Gedcom_write_hndl hndl, Gedcom_elt elt, int parsed_tag,
+ + int parent_rec_or_elt, const struct age_value* +value);
++These functions only differ in the type of the last argument, which is the value of the element.
+
+Thehndl
parameter is again the write handle returned bygedcom_write_open
. Theelt
parameter is one of the identifiers given in the first column in this table (exceptELT_USER
: see below). Theparent_rec_or_elt
is the correspondingrec
orelt
+identifier of the logically enclosing statement: this will determine the +level number written on the line, as the level number of the parent + 1.
+
+Some of the identifiers can actually stand for different tags. For this reason, theparsed_tag
has to be passed for some of them. This parsed tag is the same as was returned by the callback functions defined above, and is an identifier of the formTAG_name
. This parameter is needed whenever the second column in this table shows several possible tags (this is e.g. the case forELT_SUB_FAM_EVT
).
+
+Note that for writing a date value, the given value should be valid, i.e. +all its struct fields filled in properly and consistent. This can be +done by callinggedcom_normalize_date
(see here).
+User-defined tags
+For user-defined tags (tags starting with an underscore), there are separate functions, again depending on the data type:+
+In the case of user-defined tags, the level and tag string are passed verbatim +(not controlled by the library). This allows to write any extra data +that doesn't use a standard tag, but is only allowed for tags starting with +an underscore.int gedcom_write_user_str (Gedcom_write_hndl hndl, int level, const char* tag, const char* xrefstr,
+ const char* value);
+int gedcom_write_user_xref (Gedcom_write_hndl hndl,
int level, const char* tag, const char* xrefstr,
++ + const struct xref_value* value);
+
+
+ +Other API functions
+ + Although the above describes the basic interface of the gedcom parser, there + are some other functions that allow to customize the behaviour of the library. + These will be explained in the current section.
+
+ + +Debugging
+ The library can generate various debugging output, not only from itself, + but also the debugging output generated by the yacc parser. By default, + no debugging output is generated, but this can be customized using the +following function:
+ + ++ Thevoid gedcom_set_debug_level (int level, FILE* +trace_output)
+level
can be one of the following values:
+ + ++
+ If the- 0: no debugging information (this is the + default)
+- 1: only debugging information from libgedcom + itself
+- 2: debugging information from libgedcom + and yacc
+ + +trace_output
isNULL
, debugging information + will be written tostderr
, otherwise the given file handle + is used (which must be open).
+
+ + +Error treatment
+ One of the previous sections already described the callback to be +registered to get error messages. The library also allows to customize +what happens on an error, using the following function:
+ + ++ Thevoid gedcom_set_error_handling (Gedcom_err_mech + mechanism)
+mechanism
can be one of:
+ + ++
+ This doesn't influence the generation of error or warning messages, + only the behaviour of the parser and its return code.- +
IMMED_FAIL
: immediately fail +the parsing on an error (this is the default)- +
DEFER_FAIL
: continue parsing +after an error, but return a failure code eventually- + + +
IGNORE_ERRORS
: continue parsing + after an error, return success always
+
+ + +Compatibility mode
+ Applications are not necessarily true to the GEDCOM spec (or use a +different version than 5.5). The intention is that the library is +resilient to this, and goes in compatibility mode for files written by specific +programs (detected via the HEAD.SOUR tag). This compatibility mode +can be enabled and disabled via the following function:
+
+ + ++ The argument can be:void gedcom_set_compat_handling (int enable_compat)
+
+ + ++
+ Currently, there is (some) compatibility for:- 0: disable compatibility mode
+- 1: allow compatibility mode (this is the +default)
+ + +
+
++
+The following function allows to set some options for the compatibility handling:- ftree
+- Lifelines (3.0.2)
+- Personal Ancestral File (PAF), version 2, 4 and 5
+- Family Origins
+- EasyTree
+
++The parameter can be an OR'ed combination of the following options:void gedcom_set_compat_options (Gedcom_compat options)
+
++
+- +
COMPAT_ALLOW_OUT_OF_CONTEXT
++In some compatibility cases, tags are coming out-of-order, +i.e. their start element callback would have to come after the end element +callback of the parent tag. E.g. instead of the standard GEDCOM+
++the genealogy program has generated something like:1 DATE ...
+2 TIME ...
+
++This can give a problem if your end element callbacks free some resources.1 DATE ...
+1 TIME ...
+
- - - +If your program can handle elements out of context, you can enable this option. + By default it is disabled, and so the values of these out-of-context +tags are lost (the parser generates a warning if this is the case). Note: +currently the Gedcom object model in C has this option disabled too, although +this will change in the future.
+
+ + +
+Converting character sets
+ All strings passed by the GEDCOM parser to the application are in UTF-8 + encoding. Typically, an application needs to convert this to something + else to be able to display it.
+
+ The most common case is that the output character set is controlled by +thelocale
mechanism (i.e. via theLANG
,+ LC_ALL
orLC_CTYPE
environment variables), which also +controls thegettext
mechanism in the application.
+
With+gedcom-parse
comes a library implementing help functions for UTF-8 encoding (see +the documentation for this library).
+ + +
+ +Development support
+Macro for configure.in
+There +is a macro available for use in configure.in for applications that are using +autoconf to configure their sources. The following macro checks whether +the Gedcom parser library is available and whether its version is high enough:
+
++All the arguments are optional and default to 0. E.g. to check for +version 1.34.2, you would put in configure.in the following statement:AM_PATH_GEDCOM_PARSER([min_version,[action_if_found,[action_if_not_found,[modules]]]])
+
+Note that version numbers now contains three parts (since version +0.20.0: this is also the first version in which this macro is available).AM_PATH_GEDCOM_PARSER(1.34.2)
+
+
+The macro also sets the variablesGEDCOM_CFLAGS
andGEDCOM_LIBS
for use in Makefiles. Typically, this would be done as follows in a Makefile.am:
++If your program uses some extra modules, they can be passed as fourth argument +in the macro, so that the CFLAGS and LIBS are correctly filled in. Currently, +the only available module isbin_programs = myprg
+myprg_SOURCES = myprg.c foo.c bar.c
+INCLUDES = @GEDCOM_CFLAGS@
+LDADD = @GEDCOM_LIBS@gom
(the Gedcom object model). For example:
++To be able to use this macro in the sources of your application, you have three options:AM_PATH_GEDCOM_PARSER(0.21.2, , ,gom)
+
++
+- Put the file
+m4/gedcom.m4
in your autoconf data directory (i.e. the path given by 'aclocal --print-ac-dir
', usually/usr/share/aclocal
). You can do this automatically by going into the m4 subdirectory and typing 'make install-m4
'.
+
+- If you're using autoconf, but not automake, copy the contents of
+m4/gedcom.m4
in theaclocal.m4
file in your sources.
+
+- If you're using automake, copy the contents of
+m4/gedcom.m4
in theacinclude.m4
file in your sources.
+
+There are three preprocessor symbols defined for version checks in the + header (but their direct use is deprecated: please use the macro above):
+ ++
+ The last one is equal to- +
GEDCOM_PARSE_VERSION_MAJOR
- +
GEDCOM_PARSE_VERSION_MINOR
- + +
GEDCOM_PARSE_VERSION
+(GEDCOM_PARSE_VERSION_MAJOR * 1000) + GEDCOM_PARSE_VERSION_MINOR.
As you see, this only checked the major and minor version, not the patch number, so this is obsolete.
+
+Compilation and linking flags
+Similar to other libraries, the GEDCOM parse library installs a scriptgedcom-config
to help with compilation and linking flags for programs that don't use autoconf/automake.
+
+To get compilation flags for your program, use (depending on whether you +only use the callback parser, or also the GEDCOM object model): ++Similarly, to get linking flags, use one of the following: +gedcom-config --cflags
+gedcom-config --cflags gom
++ + + +gedcom-config --libs
+gedcom-config --libs gom
+
+ +$Id$+ + +
$Name$+ + +
+
+
+
+
+
+
+
+
+
+
+ \ No newline at end of file