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glib is a C portability and utility library for UNIX-like
systems and Windows. This chapter covers some of the most
commonly-used library features in GTK+ and Gnome
applications. glib is simple, and the concepts are
familiar; so we'll move quickly. For more complete coverage
of glib, see glib.h or the free
glib reference manual that comes with the library. (By the
way: don't be afraid of using the glib, GTK+, or Gnome
header files; they are very clean and easy to read, and are
handy as a quick reference. For that matter, don't be
afraid to look at the source code, if you have very
specific questions about the implementation.)
glib's various facilities are intended to have a consistent
interface; the coding style is semi-object-oriented, and
identifiers are prefixed with "g" to create a kind of
namespace.
glib has a single header file,
glib.h.
glib provides substitutes for many standard and
commonly-used C language constructs. This section
describes glib's fundamental type definitions, macros,
memory allocation routines, and string utility functions.
Rather than using C's standard types (int,
long, etc.) glib defines its own. These serve a
variety of purposes. For example, gint32 is guaranteed to be 32 bits
wide, something no standard C type can ensure. guint is simply easier to
type than unsigned. A
few of the typedefs exist only for consistency; for
example, gchar is
always equivalent to the standard char.
The following primitive types are defined by glib:
-
gint8, guint8, gint16, guint16, gint32, guint32, gint64, guint64---these give you
integers of a guaranteed size. Not all platforms
provide 64-bit integers; if a platform has them,
glib will define
G_HAVE_GINT64. (If it isn't obvious, the guint types are unsigned,
the gint types are
signed.)
-
gboolean is useful
to make your code more readable, since C has no
bool type.
-
gchar, gshort, glong, gint,
gfloat,
gdouble are purely cosmetic.
-
gpointer may be
more convenient to type than void *. gconstpointer gives you const void*. (const gpointer will not do what you typically mean
it to; spend some time with a good book on C if you
don't see why.)
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