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gd_get_constant(3) | GETDATA | gd_get_constant(3) |
NAME¶
gd_get_constant — retrieve a scalar constant from a dirfile databaseSYNOPSIS¶
#include <getdata.h>int
gd_get_constant(DIRFILE *dirfile, const char
*field_code, gd_type_t return_type, void
*data_out);
DESCRIPTION¶
The gd_get_constant() function queries a dirfile(5) database specified by dirfile for the CONST scalar field_code, which may contain a representation suffix. The constant is converted to the data type specified by return_type, and stored in the user-supplied buffer data_out.- GD_UINT8
- unsigned 8-bit integer
- GD_INT8
- signed (two's complement) 8-bit integer
- GD_UINT16
- unsigned 16-bit integer
- GD_INT16
- signed (two's complement) 16-bit integer
- GD_UINT32
- unsigned 32-bit integer
- GD_INT32
- signed (two's complement) 32-bit integer
- GD_UINT64
- unsigned 64-bit integer
- GD_INT64
- signed (two's complement) 64-bit integer
- GD_FLOAT32
- IEEE-754 standard 32-bit single precision floating point number
- GD_FLOAT64
- IEEE-754 standard 64-bit double precision floating point number
- GD_COMPLEX64
- C99-conformant 64-bit single precision complex number
- GD_COMPLEX128
- C99-conformant 128-bit double precision complex number
- GD_NULL
- the null type: the database is queried as usual, but no data is returned. In this case, data_out is ignored and may be NULL.
RETURN VALUE¶
On success, gd_get_constant() returns zero. On error, it returns -1 and sets the dirfile error to a non-zero value. Possible error values are:- GD_E_BAD_CODE
- The field specified by field_code was not found in the database.
- GD_E_BAD_DIRFILE
- An invalid dirfile was supplied.
- GD_E_BAD_FIELD_TYPE
- The supplied field_code referred to a field of a type other than CONST. The caller should use gd_getdata(3), or gd_get_string(3) instead.
- GD_E_BAD_REPR
- The representation suffix specified in fieldcode, or in one of the field codes it uses for input, was invalid.
- GD_E_BAD_TYPE
- An invalid return_type was specified.
- GD_E_INTERNAL_ERROR
- An internal error occurred in the library while trying to perform the task. This indicates a bug in the library. Please report the incident to the maintainer.
SEE ALSO¶
dirfile(5), gd_open(3), gd_error(3), gd_error_string(3), gd_get_carray(3), gd_constants(3), gd_put_constant(3)3 Novmeber 2010 | Version 0.7.0 |