void assert(scalar expression);
The assert() macro shall insert diagnostics into programs; it shall expand to a void expression. When it is executed, if expression (which shall have a scalar type) is false (that is, compares equal to 0), assert() shall write information about the particular call that failed on stderr and shall call abort().
The information written about the call that failed shall include the text of the argument, the name of the source file, the source file line number, and the name of the enclosing function; the latter are, respectively, the values of the preprocessing macros __FILE__ and __LINE__ and of the identifier __func__.
Forcing a definition of the name NDEBUG, either from the compiler command line or with the preprocessor control statement #define NDEBUG ahead of the #include <assert.h> statement, shall stop assertions from being compiled into the program.
The assert() macro shall not return a value.
No errors are defined.
The following sections are informative.
abort() , stderr, the Base Definitions volume of IEEE Std 1003.1-2001, <assert.h>