debian man page for fassert

FILES(3pub)						       C Programmer's Manual						       FILES(3pub)

NAME
       xgetaline, xfseek, xfopen, xfclose, getaline, fassert - file manipulation utilities

SYNOPSIS
       #include <files.h>

       FILE *xfopen(const char *filename, const char *mode);
       void xfclose(FILE *fp);
       void xfseek(FILE *fp, long offset, int origin);
       char *getaline(FILE *fp);
       char *xgetaline(FILE *fp);
       void fassert(FILE *fp);

DESCRIPTION
       These  functions  are  useful for file manipulation.  The functions that begin with x work like the functions without the letter, except if
       there is an error, they print an error message and kill the program.

       getaline reads a line from the given file.  It allocates the memory for the line with malloc(3), and returns a pointer to the beginning	of
       the  line.   If	there  is an error, it returns NULL.  If the returned value is not NULL, the caller is responsible for freeing the memory.
       The newline is removed from the end of the line.

       fassert checks that the argument is not NULL, and that (for a non-NULL argument) the file does not have its error indicator flag  set.	If
       either condition is true, it prints an error message and termiantes the program.   If neither condition is true, it does nothing.  This can
       be used to add checks that the I/O in a program is going well; however, it is mostly useful only for small programs, because  more  serious
       programs need to handle the errors more gracefully.

SEE ALSO
       publib(3)

AUTHOR
       Lars Wirzenius (lars.wirzenius@helsinki.fi)

Publib							       C Programmer's Manual						       FILES(3pub)