github.com/shijuvar/go@v0.0.0-20141209052335-e8f13700b70c/src/runtime/cgocallback.go (about)

     1  // Copyright 2011 The Go Authors.  All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package runtime
     6  
     7  import "unsafe"
     8  
     9  // These functions are called from C code via cgo/callbacks.c.
    10  
    11  // Allocate memory.  This allocates the requested number of bytes in
    12  // memory controlled by the Go runtime.  The allocated memory will be
    13  // zeroed.  You are responsible for ensuring that the Go garbage
    14  // collector can see a pointer to the allocated memory for as long as
    15  // it is valid, e.g., by storing a pointer in a local variable in your
    16  // C function, or in memory allocated by the Go runtime.  If the only
    17  // pointers are in a C global variable or in memory allocated via
    18  // malloc, then the Go garbage collector may collect the memory.
    19  //
    20  // TODO(rsc,iant): This memory is untyped.
    21  // Either we need to add types or we need to stop using it.
    22  
    23  func _cgo_allocate_internal(len uintptr) unsafe.Pointer {
    24  	if len == 0 {
    25  		len = 1
    26  	}
    27  	ret := unsafe.Pointer(&make([]unsafe.Pointer, (len+ptrSize-1)/ptrSize)[0])
    28  	c := new(cgomal)
    29  	c.alloc = ret
    30  	gp := getg()
    31  	c.next = gp.m.cgomal
    32  	gp.m.cgomal = c
    33  	return ret
    34  }
    35  
    36  // Panic.
    37  
    38  func _cgo_panic_internal(p *byte) {
    39  	panic(gostringnocopy(p))
    40  }