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Source file src/runtime/cgo/callbacks.go

Documentation: runtime/cgo

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

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