ASSERT(3C) Standard C Library Functions ASSERT(3C)

NAME

assert - verify program assertion

SYNOPSIS

#include <assert.h>

void assert(int expression);

DESCRIPTION

The assert() macro inserts diagnostics into applications. When
executed, if expression is FALSE (zero), assert() prints the error
message

Assertion failed: expression, file xyz, line nnn


on the standard error output and aborts. In the error message, xyz is
the name of the source file and nnn the source line number of the
assert() statement. These are respectively the values of the
preprocessor macros __FILE__ and __LINE__.


Since assert() is implemented as a macro, the expression may not
contain any string literals.


Compiling with the preprocessor option -DNDEBUG or with the
preprocessor control statement #define NDEBUG ahead of the #include
<assert.h> statement, will stop assertions from being compiled into
the program.


Messages printed from this function are in the native language
specified by the LC_MESSAGES locale category. See setlocale(3C).

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|MT-Level | Safe |
+--------------------+-------------------+
|Standard | See standards(7). |
+--------------------+-------------------+

SEE ALSO

abort(3C), gettext(3C), setlocale(3C), attributes(7), standards(7)

March 30, 2005 ASSERT(3C)