Setjmp. H in C

This guide covers setjmp. h in c with practical context and easy-to-follow details. Use it to understand the subject and apply the information confidently.

Setjmp. H in C

The Variable Is Defined in Setjmp. H

Here is the type of variable defined in setjmp. H:

Jmp_buf : This is an array type used to hold information for the setjmp () macro and longjmp () function.

The Macros Are Defined in Setjmp. H

There is only one macro defined in this library:

Int setjmp (jmp_buf environment) : This macro stores the current environment inside the environment variable for later use by longjmp (). If this macro returns directly from the macro call, it returns 0; but if it returns from a call to longjmp (), a value other than 0 is returned.

Macro declaration setjmp () in C

Below is the declaration for setjmp () macro.

 int setjmp (jmp_buf environment) 

Parameters:

Environment - This is an object of type jmp_buf where environment information is stored.

Return value:

This macro returns more than 1 time. First, on its direct call, it always returns 0. When longjmp is called with the information set to the environment, this macro returns again; this time it returns the value passed to longjmp as the second parameter.

For example:

The following C program illustrates the usage of setjmp () macro.

 #include 
 #include 
 #include 

 main () 
 { 
 jmp_buf env; 
 int i; 

 i = setjmp (env); 
 printf ("i =% dn", i); 

 if (i! = 0) exit (0); 

 longjmp (env, 2); 
 printf ("Is it printed now?"); 

 } 

Compiling and running the above C program will result:

 i = 0 
 i = 2 

The Functions Are Defined in Setjmp. H

Only one function is defined in setjmp. H:

Function longjmp void (jmp_buf environment, int value): This function restores the environment (environment) stored by the closest call to the setjmp () macro in the same function call of the program with the corresponding parameter jmp_buf.

Declare the function longjmp () in C

Below is the declaration for longjmp () function in C:

 void longjmp (jmp_buf environment, int value) 

Parameters:

Environment - This is an object of type jmp_buf that contains information to store the environment at the call point of setjmp. Value - This is the value for the setjmp expression to estimate.

Return value:

This function does not return any values.

For example:

The following program C illustrates the usage of the longjmp () function in C:

 #include 
 #include 
 #include 

 main () 
 { 
 jmp_buf env; 
 int i; 

 i = setjmp (env); 
 printf ("i =% dn", i); 

 if (i! = 0) exit (0); 

 longjmp (env, 2); 
 printf ("Is it printed now?"); 

 } 

Compiling and running the above C program will result:

 i = 0 
 i = 2 

According to Tutorialspoint

Last lesson: math. H in C

Next post: signal. H in C