Source file src/runtime/cgo/callbacks.go

     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 cgo
     6  
     7  import "unsafe"
     8  
     9  // These utility functions are available to be called from code
    10  // compiled with gcc via crosscall2.
    11  
    12  // The declaration of crosscall2 is:
    13  //   void crosscall2(void (*fn)(void *), void *, int);
    14  //
    15  // We need to export the symbol crosscall2 in order to support
    16  // callbacks from shared libraries. This applies regardless of
    17  // linking mode.
    18  //
    19  // Compatibility note: SWIG uses crosscall2 in exactly one situation:
    20  // to call _cgo_panic using the pattern shown below. We need to keep
    21  // that pattern working. In particular, crosscall2 actually takes four
    22  // arguments, but it works to call it with three arguments when
    23  // calling _cgo_panic.
    24  //
    25  //go:cgo_export_static crosscall2
    26  //go:cgo_export_dynamic crosscall2
    27  
    28  // Panic. The argument is converted into a Go string.
    29  
    30  // Call like this in code compiled with gcc:
    31  //   struct { const char *p; } a;
    32  //   a.p = /* string to pass to panic */;
    33  //   crosscall2(_cgo_panic, &a, sizeof a);
    34  //   /* The function call will not return.  */
    35  
    36  // TODO: We should export a regular C function to panic, change SWIG
    37  // to use that instead of the above pattern, and then we can drop
    38  // backwards-compatibility from crosscall2 and stop exporting it.
    39  
    40  //go:linkname _runtime_cgo_panic_internal runtime._cgo_panic_internal
    41  func _runtime_cgo_panic_internal(p *byte)
    42  
    43  //go:linkname _cgo_panic _cgo_panic
    44  //go:cgo_export_static _cgo_panic
    45  //go:cgo_export_dynamic _cgo_panic
    46  func _cgo_panic(a *struct{ cstr *byte }) {
    47  	_runtime_cgo_panic_internal(a.cstr)
    48  }
    49  
    50  //go:cgo_import_static x_cgo_init
    51  //go:linkname x_cgo_init x_cgo_init
    52  //go:linkname _cgo_init _cgo_init
    53  var x_cgo_init byte
    54  var _cgo_init = &x_cgo_init
    55  
    56  //go:cgo_import_static x_cgo_thread_start
    57  //go:linkname x_cgo_thread_start x_cgo_thread_start
    58  //go:linkname _cgo_thread_start _cgo_thread_start
    59  var x_cgo_thread_start byte
    60  var _cgo_thread_start = &x_cgo_thread_start
    61  
    62  // Creates a new system thread without updating any Go state.
    63  //
    64  // This method is invoked during shared library loading to create a new OS
    65  // thread to perform the runtime initialization. This method is similar to
    66  // _cgo_sys_thread_start except that it doesn't update any Go state.
    67  
    68  //go:cgo_import_static x_cgo_sys_thread_create
    69  //go:linkname x_cgo_sys_thread_create x_cgo_sys_thread_create
    70  //go:linkname _cgo_sys_thread_create _cgo_sys_thread_create
    71  var x_cgo_sys_thread_create byte
    72  var _cgo_sys_thread_create = &x_cgo_sys_thread_create
    73  
    74  // Notifies that the runtime has been initialized.
    75  //
    76  // We currently block at every CGO entry point (via _cgo_wait_runtime_init_done)
    77  // to ensure that the runtime has been initialized before the CGO call is
    78  // executed. This is necessary for shared libraries where we kickoff runtime
    79  // initialization in a separate thread and return without waiting for this
    80  // thread to complete the init.
    81  
    82  //go:cgo_import_static x_cgo_notify_runtime_init_done
    83  //go:linkname x_cgo_notify_runtime_init_done x_cgo_notify_runtime_init_done
    84  //go:linkname _cgo_notify_runtime_init_done _cgo_notify_runtime_init_done
    85  var x_cgo_notify_runtime_init_done byte
    86  var _cgo_notify_runtime_init_done = &x_cgo_notify_runtime_init_done
    87  
    88  // Sets the traceback context function. See runtime.SetCgoTraceback.
    89  
    90  //go:cgo_import_static x_cgo_set_context_function
    91  //go:linkname x_cgo_set_context_function x_cgo_set_context_function
    92  //go:linkname _cgo_set_context_function _cgo_set_context_function
    93  var x_cgo_set_context_function byte
    94  var _cgo_set_context_function = &x_cgo_set_context_function
    95  
    96  // Calls a libc function to execute background work injected via libc
    97  // interceptors, such as processing pending signals under the thread
    98  // sanitizer.
    99  //
   100  // Left as a nil pointer if no libc interceptors are expected.
   101  
   102  //go:cgo_import_static _cgo_yield
   103  //go:linkname _cgo_yield _cgo_yield
   104  var _cgo_yield unsafe.Pointer
   105  
   106  //go:cgo_export_static _cgo_topofstack
   107  //go:cgo_export_dynamic _cgo_topofstack
   108  

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