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/** @file ../include/setjmp.h
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@internalComponent
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*/
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/** @fn longjmp(jmp_buf __jmpb, int __retval)
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@param __jmpb
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@param __retval
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Refer to setjmp() for the documentation
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@publishedAll
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@externallyDefinedApi
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*/
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/** @fn setjmp(jmp_buf __jmpb)
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@param __jmpb
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Note: This description also covers the following functions -
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longjmp() _setjmp() _longjmp()
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@return If the return is from a direct invocation, the setjmp function returns 0. If the return is from a call to longjmp(),
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setjmp() returns a non-zero value.
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After the longjmp is completed, program execution continues as if
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the corresponding invocation of setjmp() had just returned the
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value specified by __retval. If __retval is 0, setjmp() returns 1.
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The setjmp, and _setjmp functions save their calling environment in __jmpb. Each of these functions returns 0.
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The corresponding longjmp functions restore the environment saved by their most recent respective
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invocations
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of the setjmp function.
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They then return so that program execution continues as if the corresponding
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invocation of the setjmp call had just returned the value specified by __retval, instead of 0.
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The longjmp routines may not be called after the routine which called the setjmp routines returns.
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All accessible objects have values as of the time longjmp routine was called, except that the values of objects of automatic storage
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invocation duration that do not have the volatile
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type and have been changed between the setjmp invocation and longjmp call are indeterminate.
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The setjmp / longjmp pairs save and restore the signal mask while _setjmp / _longjmp pairs save and restore only the register set and the stack.
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Examples:
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@code
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#include <setjmp.h>
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#include <stdio.h>
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#include <stdlib.h>
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static void f1( int, int, int );
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static void f2( void );
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static jmp_buf jmpbuffer;
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int main()
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{
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int count;
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register int val;
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volatile int sum;
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count = 2; val = 3; sum = 4;
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if ( setjmp( jmpbuffer ) != 0 )
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{
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printf("in main: count = %d, val = %d, sum = %d
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", count, val, sum );
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exit(0);
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}
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f1(97, 98, 99 );
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return 0;
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}
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static void f1 (int i, int j, int k )
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{
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printf("in f1: count = %d, val = %d, sum = %d
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", i, j , k );
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f2();
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}
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static void f2( void )
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{
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longjmp( jmpbuffer, 1 );
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}
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@endcode
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Output
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@code
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in f1: count = 97, val = 98, sum = 99
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in main: count = 2, val = 3, sum = 4
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@endcode
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Limitations:
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The signal related functionalities aren't applicable to the Symbian
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OS implementation as there is no support for signals. This means that the setjmp and _setjmp routines have the same functionality and so do longjmp and _longjmp .
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@publishedAll
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@externallyDefinedApi
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*/
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/** @def _setjmp
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The _longjmp() and _setjmp() functions shall be equivalent to longjmp() and setjmp(), respectively, with the additional restriction that _longjmp() and _setjmp() shall not manipulate the signal mask.
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@publishedAll
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@externallyDefinedApi
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*/
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/** @def _longjmp
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The _longjmp() and _setjmp() functions shall be equivalent to longjmp() and setjmp(), respectively, with the additional restriction that _longjmp() and _setjmp() shall not manipulate the signal mask.
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@publishedAll
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@externallyDefinedApi
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*/
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