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C166 User's Guide

C166 Introduction Compiling Programs Language Extensions Preprocessor Advanced Programming Error Messages Library Reference Library Files Source Code Standard Types jmp_buf ptrdiff_t size_t va_list wchar_t Macros HARRAY HVAR MARRAY MVAR XARRAY XVAR Routines By Category Buffer Manipulation Routines Character Routines Data Conversion Routines Intrinsic Routines Math Routines Memory Allocation Routines Stream I/O Routines String Routines Variable Length Argument Routines Miscellaneous Routines Include Files SFR Definitions absacc.h assert.h ctype.h float.h intrins.h limits.h math.h membox.h setjmp.h stdarg.h stddef.h stdio.h stdlib.h string.h Reference _alloc_boxf _alloc_boxh _alloc_boxn _atomic_ _bfld_ _calloc_boxf _calloc_boxh _calloc_boxn _chkdouble_ _chkfloat_ _crol_ _cror_ _diswdt_ _einit_ _endatomic_ _free_boxf _free_boxh _free_boxn _getkey _idle_ _init_boxf _init_boxh _init_boxn _irol_ _iror_ _lrol_ _lror_ _nop_ _pop_ _prior_ _priord_ _push_ _pwrdn_ _sof_ _srvwdt_ _testclear_ _testset_ _tolower _toupper _trap_ abs acos asin assert atan atan2 atof atoi atol calloc calloc_b ceil cos cosh exp fabs floor fmemccpy fmemchr fmemcmp fmemcpy fmemmove fmemset fmod free free_b fstrcat fstrchr fstrcmp fstrcpy fstrcspn fstrlen fstrncat fstrncmp fstrncpy fstrpbrk fstrpos fstrrchr fstrrpbrk fstrrpos fstrspn getchar gets hmemcmp hmemcpy hstrcmp hstrcpy init_mempool init_mempool_b isalnum isalpha iscntrl isdigit isgraph islower isprint ispunct isspace isupper isxdigit labs log log10 longjmp malloc malloc_b memccpy memchr memcmp memcpy memmove memset modf offsetof pow printf putchar puts rand realloc realloc_b scanf setjmp sin sinh sprintf sqrt srand sscanf strcat strchr strcmp strcpy strcspn strlen strncat strncmp strncpy strpbrk strpos strrchr strrpbrk strrpos strspn strstr strtod strtol strtoul tan tanh toascii toint tolower toupper ungetchar va_arg va_end va_start vprintf vsprintf xcalloc xfree xinit_mempool xmalloc xmemccpy xmemchr xmemcmp xmemcpy xmemmove xmemset xrealloc xstrcmp xstrcpy xstrlen xstrncpy Appendix

setjmp

Summary
#include <setjmp.h>

int setjmp (
  jmp_buf env);      /* current environment */
Description

The setjmp function saves the current state of the CPU in env. The state may be restored by a subsequent call to the longjmp function. When used together, the setjmp and longjmp functions provide you with a way to execute a non-local goto.

A call to the setjmp function saves the current instruction address as well as other CPU registers. A subsequent call to the longjmp function restores the instruction pointer and registers, and execution resumes at the point just after the setjmp call.

Local variables and function arguments are restored only if declared with the volatile attribute.

Return Value

The setjmp function returns a value of 0 when the current state of the CPU has been copied to env. A non-zero value indicates that the longjmp function was executed to return to the setjmp function call. In such a case, the return value is the value passed to the longjmp function.

See Also

longjmp

Example
#include <setjmp.h>
#include <stdio.h> /* for printf */

jmp_buf env; /* jump environment (must be global) */
bit error_flag;

void trigger (void) {
  .
  .
  .
  /* processing code here */
  .
  .
  .
  if (error_flag != 0) {
    longjmp (env, 1);   /* return 1 to setjmp */
  }
  .
  .
  .
}


void recover (void) {
  /* recovery code here */
}


void tst_longjmp (void) {
  .
  .
  .
  if (setjmp (env) != 0) {     /* setjmp returns a 0 */
    printf ("LONGJMP called\n");
    recover ();
  }

  else {
    printf ("SETJMP called\n");

    error_flag = 1;            /* force an error */

    trigger ();
  }
}

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