GVALUEHOLDSINTvalue

GVALUEHOLDSINTvalue is commonly understood as the macro G_VALUE_HOLDS_INT used in GLib’s GValue type system. It serves as a runtime type check to determine whether a GValue currently stores a value of type int (often corresponding to the GLib type G_TYPE_INT or the C int type, depending on the platform).

In GLib, GValue is a generic container that can hold values of various types. The G_VALUE_HOLDS_INT macro evaluates whether the value’s stored type matches an integer type, allowing code to safely retrieve the value with g_value_get_int after confirming the type. This pattern is part of a larger family of macros, such as G_VALUE_HOLDS_DOUBLE or G_VALUE_HOLDS_STRING, that enable type-safe access to a GValue’s contents at runtime.

Typical usage involves initializing a GValue with a specific type, manipulating it, and then using G_VALUE_HOLDS_INT to check the stored type before calling g_value_get_int. For example: g_value_init(&val, G_TYPE_INT); g_value_set_int(&val, 42); if (G_VALUE_HOLDS_INT(&val)) { int i = g_value_get_int(&val); / use i / }

Limitations to note include that the macro only tests the current stored type; it does not perform type conversion. If the value was initialized with a different type, or if an incompatible type was set, the macro would indicate that the value does not hold an int. This macro is part of GLib’s broader approach to dynamic typing in C, supporting flexible property and parameter handling in GObject-based code.