Header File 

assert.h 

Category 

Diagnostic Routines 

Prototype 

void assert(int test); 

Description 

Tests a condition and possibly aborts. 

assert is a macro that expands to an if statement; if test evaluates to zero, the assert macro calls the _assert function 

void _RTLENTRY _EXPFUNC _assert(char * __cond, char * __file, int __line); 

and aborts the program. The _assert function calls abort and asserts the following a message on stderr: 

Assertion failed: test, file filename, line linenum 

The filename and linenum listed in the message are the source file name and line number where the assert macro appears. 

If you place the #define NDEBUG directive ("no debugging") in the source code before the #include <assert.h> directive, the macro expands to a no-op, the effect is to comment out the assert statement. 

Return Value 

None. 

Example  

 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 struct ITEM {
    int key;
    int value;
 };
 /* add item to list, make sure list is not  null */
 void additem(struct ITEM *itemptr) {
    assert(itemptr != NULL);
    /* add item to list */
 }
 int main(void)
 {
    additem(NULL);
    return 0;
 }

Portability