Warning: This is the manual of the legacy Guile 2.0 series. You may want to read the manual of the current stable series instead.
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The first impedance mismatch that one sees between C and Scheme is that in C, the storage locations (variables) are typed, but in Scheme types are associated with values, not variables. See Values and Variables.
So when describing a C function or a C structure so that it can be accessed from Scheme, the data types of the parameters or fields must be passed explicitly.
These “C type values” may be constructed using the constants and
procedures from the (system foreign)
module, which may be loaded
like this:
(use-modules (system foreign))
(system foreign)
exports a number of values expressing the basic
C types:
These values represent the C numeric types of the specified sizes and signednesses.
In addition there are some convenience bindings for indicating types of platform-dependent size:
Values exported by the (system foreign)
module, representing C
numeric types. For example, long
may be equal?
to
int64
on a 64-bit platform.
The void
type. It can be used as the first argument to
pointer->procedure
to wrap a C function that returns nothing.
In addition, the symbol *
is used by convention to denote pointer
types. Procedures detailed in the following sections, such as
pointer->procedure
, accept it as a type descriptor.
Next: Foreign Variables, Up: Foreign Pointers [Contents][Index]