lib/c-stack.h

/* Stack overflow handling.

   Copyright (C) 2002, 2004, 2008-2026 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* This file uses _GL_ASYNC_SAFE.  */
#if !_GL_CONFIG_H_INCLUDED
 #error "Please include config.h first."
#endif

#ifdef __cplusplus
extern "C"
{
#endif

/* Set up ACTION so that it is invoked on C stack overflow and on other,
   stack-unrelated, segmentation violation.
   Return -1 (setting errno) if this cannot be done.

   When a stack overflow or segmentation violation occurs:
   1) ACTION is called.  It is passed an argument equal to
        - 0, for a stack overflow,
        - SIGSEGV, for a segmentation violation that does not appear related
          to stack overflow.
      On many platforms the two cases are hard to distinguish; when in doubt,
      zero is passed.
   2) If ACTION returns, a message is written to standard error, and the
      program is terminated: in the case of stack overflow, with exit code
      exit_failure (see "exitfail.h"), otherwise through a signal SIGSEGV.

   A null ACTION acts like an action that does nothing.

   Restrictions:
   - ACTION must be async-signal-safe.
   - ACTION together with its callees must not require more than 64 KiB of
     stack space.
   - ACTION must not create and then invoke nested functions
     <https://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html>, because
     this implementation does not guarantee an executable stack.
   - ACTION should not call longjmp, because this implementation does not
     guarantee that it is safe to return to the original stack.

   This function may install a handler for the SIGSEGV signal or for the SIGBUS
   signal or exercise other system dependent exception handling APIs.  */

extern int c_stack_action (_GL_ASYNC_SAFE void (* /*action*/) (int));

#ifdef __cplusplus
}
#endif