5.11 Function Types
Various types can be defined for function variables. These types are not used in defining functions (see Procedures); they are used for things like pointers to functions.
The simple, traditional, type is type descriptor f is followed by type information for the return type of the function, followed by a semicolon.
This does not deal with functions for which the number and types of the parameters are part of the type, as in Modula-2 or ANSI C. AIX provides extensions to specify these, using the f, F, p, and R type descriptors.
First comes the type descriptor. If it is f or F, this type involves a function rather than a procedure, and the type information for the return type of the function follows, followed by a comma. Then comes the number of parameters to the function and a semicolon. Then, for each parameter, there is the name of the parameter followed by a colon (this is only present for type descriptors R and F which represent Pascal function or procedure parameters), type information for the parameter, a comma, 0 if passed by reference or 1 if passed by value, and a semicolon. The type definition ends with a semicolon.
For example, this variable definition:
generates the following code:
.stabs "g_pf:G24=*25=f1",32,0,0,0 .common _g_pf,4,"bss"
The variable defines a new type, 24, which is a pointer to another new
type, 25, which is a function returning