.\"	@(#)assert.3	6.2 (Berkeley) 5/12/86
.\"
.TH ASSERT 3 "May 12, 1986"
.AT 3
.SH NAME
assert \- program verification
.SH SYNOPSIS
.nf
.ft B
#include <assert.h>

void assert(int \fIexpression\fP)
.fi
.SH DESCRIPTION
.B Assert
is a macro that indicates
.I expression
is expected to be true at this point in the program.
It causes an
.BR abort (3)
with a diagnostic comment on the standard output when
.I expression
is false (0).
Compiling with the 
.BR cc (1)
option
.SM
.B \-DNDEBUG
effectively deletes
.B assert
from the program.
.SH DIAGNOSTICS
`Assertion "\fIexpression\fR" failed: file
.I f
line
.IR n .'
.I F
is the source file and
.I n
the source line number of the
.B assert
statement.