*** UNIX MANUAL PAGE BROWSER ***

assert(3) Library Functions Manual assert(3) NAME assert - Inserts program diagnostics LIBRARY Standard C Library (libc.a, libc.so) SYNOPSIS #include <assert.h> void assert( int expression) ; STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: assert(): XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. PARAMETERS Specifies an expression that is evaluated as TRUE or FALSE. This ex- pression is evaluated in the same manner as a C language if control statement. DESCRIPTION The assert() macro inserts diagnostics into programs. On execution, when the expression parameter is false (returns FALSE), this macro writes information about the particular call that failed, including the text of the argument, the name of the source file, and the source-file line number (the latter two are respectively the values of preprocess- ing macros __FILE__ and __LINE__) on stderr. The error message is taken from the standard C library message catalog. The assert() macro then calls the abort() function to (normally) terminate the process. When you compile a program with the -DNDEBUG preprocessor option, or with the #define NDEBUG preprocessor control statement before the #in- clude <assert.h> statement, calls to the assert() macro have no effect. RETURN VALUES The assert() function returns no value. RELATED INFORMATION Routines: abort(3) Standards: standards(5) delim off assert(3)