gd_add_spec man page
gd_add_spec, gd_madd_spec — add a field to a Dirfile
int gd_add_spec(DIRFILE *dirfile, const char *line, int fragment_index);
int gd_madd_spec(DIRFILE *dirfile, const char *line, const char *parent);
The gd_add_spec() function adds the field described by the field specification line in line to the dirfile specified by dirfile. The gd_madd_spec() function behaves similarly, but adds the field as a metafield under the field indicated by the field parent. Field specification lines are described in detail in dirfile-format(5). Since Standards Version 7 (see dirfile(5)) permits specifying metafield without the use of the /META directive, gd_add_spec() may also be used to add metafields, by specifying the metafield's full field code. See dirfile-format(5) for full details.
When using gd_madd_spec(), line should only contain a field specification, and not a /META directive.
Passing these functions a directive line instead of a field specification line will result in a syntax error. These functions never call the registered parser callback function, even if line contains a syntax error.
On success, gd_add_spec() and gd_madd_spec() return zero. On error, a negative-valued error code is returned. Possible error codes are:
The specified dirfile was opened read-only.
The library was unable to allocate memory.
The parent field code was not found, or was already a metafield.
The supplied dirfile was invalid.
The fragment_index argument was out of range.
A syntax error was encountered in line.
An I/O error occurred while creating an empty binary file to be associated with a newly added RAW field.
The supplied line was longer than the parser was able to deal with. Line lengths are limited by the storage size of size_t.
The metadata of the fragment was protected from change. Or, the creation of a RAW field was attempted and the data of the fragment was protected.
The encoding scheme of the indicated format specification fragment is not known to the library. As a result, the library was unable to create an empty binary file to be associated with a newly added RAW field.
The encoding scheme of the indicated format specification fragment does not support creating an empty binary file to be associated with a newly added RAW field.
The error code is also stored in the DIRFILE object and may be retrieved after this function returns by calling gd_error(3). A descriptive error string for the error may be obtained by calling gd_error_string(3).
The functions dirfile_add_spec() and dirfile_madd_spec() appeared in GetData-0.4.0.
In GetData-0.7.0, these functions were renamed to gd_add_spec() and gd_madd_spec().
In GetData-0.10.0, the error return from these functions changed from -1 to a negative-valued error code.
gd_add(3), all the gd_add_<entry-type> functions (e.g., gd_add_bit(3)), gd_error(3), gd_error_string(3), gd_madd(3), all the gd_madd_<entry-type> functions (e.g., gd_madd_bit(3)), gd_metaflush(3), gd_open(3), dirfile-format(5)
dirfile-encoding(5), gd_add(3), gd_add_bit(3), gd_madd_bit(3).