Merge pull request #30019 from sebasguts/sg/ccall_docs

Extended ccall documentation

Author: vchuravy

base/docs/basedocs.jl

@@ -618,11 +618,13 @@ kw"||"
 
 """
     ccall((function_name, library), returntype, (argtype1, ...), argvalue1, ...)
+    ccall(function_name, returntype, (argtype1, ...), argvalue1, ...)
     ccall(function_pointer, returntype, (argtype1, ...), argvalue1, ...)
 
 Call a function in a C-exported shared library, specified by the tuple `(function_name, library)`,
-where each component is either a string or symbol. Alternatively, `ccall` may
-also be used to call a function pointer `function_pointer`, such as one returned by `dlsym`.
+where each component is either a string or symbol. Instead of specifying a library,
+one can also use a `function_name` symbol or string, which is resolved in the current process.
+Alternatively, `ccall` may also be used to call a function pointer `function_pointer`, such as one returned by `dlsym`.
 
 Note that the argument type tuple must be a literal tuple, and not a tuple-valued
 variable or expression.

doc/src/manual/calling-c-and-fortran-code.md

@@ -44,6 +44,11 @@ to [`ccall`](@ref) are as follows:
 
    OR
 
+   a `:function` name symbol or `"function"` name string, which is resolved in the
+   current process,
+
+   OR
+
    a function pointer (for example, from `dlsym`).
 
 2. Return type (see below for mapping the declared C type to Julia)