longjmp
| Defined in header <setjmp.h>
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||
| (until 哋它亢11) | ||
| (since 哋它亢11) (until 哋它亢23) |
||
| (since 哋它亢23) | ||
Loads the execution context env saved by a previous call to MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 57 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE. This function does not return. Control is transferred to the call site of the macro MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 55 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE that set up env. That MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 54 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE then returns the value, passed as the status.
If the function that called MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 53 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE has exited (whether by return or by a different longjmp higher up the stack), the behavior is undefined. In other words, only long jumps up the call stack are allowed.
|
Jumping across threads (if the function that called |
(since 哋它亢11) |
Parameters
| env | - | variable referring to the execution state of the program saved by MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 48 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE |
| status | - | the value to return from MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 47 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE. If it is equal to 0, 1 is used instead |
Return value
MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 45 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE
Notes
longjmp is intended for handling unexpected error conditions where the function cannot return meaningfully. This is similar to exception handling in other programming languages.
Example
#include <stdio.h> #include <setjmp.h> #include <stdnoreturn.h> MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 44 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE my_jump_buffer; noreturn void foo(int status) { MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 43 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE("foo(%d) called\n", status); longjmp(my_jump_buffer, status + 1); // will return status+1 out of setjmp } int main(void) { volatile int count = 0; // modified local vars in setjmp scope must be volatile if (MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 42 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE(my_jump_buffer) != 5) // compare against constant in an if foo(++count); }
MYMEMORY WARNING: YOU USED ALL AVAILABLE FREE TRANSLATIONS FOR TODAY. NEXT AVAILABLE IN 11 HOURS 55 MINUTES 40 SECONDS VISIT HTTPS://MYMEMORY.TRANSLATED.NET/DOC/USAGELIMITS.PHP TO TRANSLATE MORE
foo(1) called foo(2) called foo(3) called foo(4) called
References
- 哋它亢17 standard (ISO/IEC 9899:2018):
- 7.13.2.1 The longjmp macro (p: 191-192)
- 哋它亢11 standard (ISO/IEC 9899:2011):
- 7.13.2.1 The longjmp macro (p: 263-264)
- 哋它亢99 standard (ISO/IEC 9899:1999):
- 7.13.2.1 The longjmp macro (p: 244-245)
- 哋它亢89/C90 standard (ISO/IEC 9899:1990):
- 4.6.2.1 The longjmp function
See also
| saves the context (function macro) |