setjmp(3p) [centos man page]
SETJMP(3P) POSIX Programmer's Manual SETJMP(3P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
setjmp - set jump point for a non-local goto SYNOPSIS
#include <setjmp.h> int setjmp(jmp_buf env); DESCRIPTION
A call to setjmp() shall save the calling environment in its env argument for later use by longjmp(). It is unspecified whether setjmp() is a macro or a function. If a macro definition is suppressed in order to access an actual function, or a program defines an external identifier with the name setjmp, the behavior is undefined. An application shall ensure that an invocation of setjmp() appears in one of the following contexts only: * The entire controlling expression of a selection or iteration statement * One operand of a relational or equality operator with the other operand an integral constant expression, with the resulting expression being the entire controlling expression of a selection or iteration statement * The operand of a unary '!' operator with the resulting expression being the entire controlling expression of a selection or iteration * The entire expression of an expression statement (possibly cast to void) If the invocation appears in any other context, the behavior is undefined. RETURN VALUE
If the return is from a direct invocation, setjmp() shall return 0. If the return is from a call to longjmp(), setjmp() shall return a non- zero value. ERRORS
No errors are defined. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
In general, sigsetjmp() is more useful in dealing with errors and interrupts encountered in a low-level subroutine of a program. RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
longjmp(), sigsetjmp(), the Base Definitions volume of IEEE Std 1003.1-2001, <setjmp.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . IEEE
/The Open Group 2003 SETJMP(3P)
Check Out this Related Man Page
LONGJMP(3P) POSIX Programmer's Manual LONGJMP(3P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
longjmp - non-local goto SYNOPSIS
#include <setjmp.h> void longjmp(jmp_buf env, int val); DESCRIPTION
The longjmp() function shall restore the environment saved by the most recent invocation of setjmp() in the same thread, with the corre- sponding jmp_buf argument. If there is no such invocation, or if the function containing the invocation of setjmp() has terminated execu- tion in the interim, or if the invocation of setjmp() was within the scope of an identifier with variably modified type and execution has left that scope in the interim, the behavior is undefined. It is unspecified whether longjmp() restores the signal mask, leaves the sig- nal mask unchanged, or restores it to its value at the time setjmp() was called. All accessible objects have values, and all other components of the abstract machine have state (for example, floating-point status flags and open files), as of the time longjmp() was called, except that the values of objects of automatic storage duration are unspecified if they meet all the following conditions: * They are local to the function containing the corresponding setjmp() invocation. * They do not have volatile-qualified type. * They are changed between the setjmp() invocation and longjmp() call. As it bypasses the usual function call and return mechanisms, longjmp() shall execute correctly in contexts of interrupts, signals, and any of their associated functions. However, if longjmp() is invoked from a nested signal handler (that is, from a function invoked as a result of a signal raised during the handling of another signal), the behavior is undefined. The effect of a call to longjmp() where initialization of the jmp_buf structure was not performed in the calling thread is undefined. RETURN VALUE
After longjmp() is completed, program execution continues as if the corresponding invocation of setjmp() had just returned the value speci- fied by val. The longjmp() function shall not cause setjmp() to return 0; if val is 0, setjmp() shall return 1. ERRORS
No errors are defined. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
Applications whose behavior depends on the value of the signal mask should not use longjmp() and setjmp(), since their effect on the signal mask is unspecified, but should instead use the siglongjmp() and sigsetjmp() functions (which can save and restore the signal mask under application control). RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
setjmp(), sigaction(), siglongjmp(), sigsetjmp(), the Base Definitions volume of IEEE Std 1003.1-2001, <setjmp.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . IEEE
/The Open Group 2003 LONGJMP(3P)