182 Programming
but Joey doesn’t know that. Or maybe he is using quotes but is using a
compiler with slightly different search rules for include files. The point is
that Joey is hosed, and it’s probably not his fault.Having a large number of header files is a big pain. Unfortunately, this sit-
uation occurs whenever you try to write a C program that does anything
useful. Header files typically define data structures and many header files
depend on data structures defined in other header files. You, as the pro-
grammer, get the wonderful job of sorting out these dependencies and
including the header files in the right order.Of course, the compiler will help you. If you get the order wrong, the com-
piler will testily inform you that you have a syntax error. The compiler is a
busy and important program and doesn’t have time to figure out the differ-
ence between a missing data structure definition and a plain old mistyped
word. In fact, if you make even a small omission, like a single semicolon, a
C compiler tends to get so confused and annoyed that it bursts into tears
and complains that it just can’t compile the rest of the file since the one
missing semicolon has thrown it off so much. The poor compiler just can’t
concentrate on the rest.In the compiler community, this phenomenon is known as “cascade
errors,” which is compiler jargon for “I’ve fallen and I can’t get up.” The
missing semicolon has thrown the compiler’s parser out of sync with
respect to the program text. The compiler probably has such a hard time
with syntax error because it’s based on yacc, which is a great tool for pro-
ducing parsers for syntactically correct programs (the infrequent case), but
a horrible tool for producing robust, error-detecting and -correcting pars-
ers. Experienced C programmers know to ignore all but the first parse error
from a compiler.Utility Programs and Man Pages
Unix utilities are self-contained; each is free to interpret its command-line
arguments as it sees fit. This freedom is annoying; instead of being able to
learn a single set of conventions for command line arguments, you have to
read a man page for each program to figure out how to use it.It’s a good thing the man pages are so well written.Take this following example. The “SYNOPSIS” sums it up nicely, don’t
you think?