Diagnostic Printed by the assert Function

ANSI 4.2   The diagnostic printed by and the termination behavior of the assert function

The assert function prints a diagnostic message and calls the abort routine if the expression is false (0). The diagnostic message has the form

Assertion failed: expression, file filename, line linenumber

where filename is the name of the source file and linenumber is the line number of the assertion that failed in the source file. No action is taken if expression is true (nonzero).