ASSERT(3) BSD Programmer's Manual ASSERT(3)
assert - expression verification macro
The assert() macro tests the given expression and if it is false, the
calling process is terminated. A diagnostic message is written to the
stderr and the function _exit(2) is called effectively terminating the
If expression is true, the assert() macro does nothing.
The assert() macro may be removed at compile time with the -NDEBUG op-
tion, see cc(1).
The following diagnostic message is written to stderr if expression is
"assertion \"%s\" failed: file \"%s\", line %d0, \
"expression", __FILE__, __LINE__);
A assert macro appeared in Version 6 AT&T UNIX.
4.4BSD June 9, 1993 1