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Imported from libpng-1.0.7rc1.tar

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Glenn Randers-Pehrson
2000-06-09 08:46:21 -05:00
parent db66d44801
commit 1f2d559f70
52 changed files with 190 additions and 202 deletions
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37
contrib/visupng/cexcept.h
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@@ -1,5 +1,5 @@
/*===
cexcept.h 1.0.0 (2000-Jun-21-Wed)
cexcept.h 0.6.1 (2000-Apr-22-Sat)
Adam M. Costello <amc@cs.berkeley.edu>
An interface for exception-handling in ANSI C, developed jointly with
@@ -107,15 +107,14 @@ Catch (expression) statement
confusion with the C++ keywords, which have subtly different
semantics.
A Try/Catch statement has a syntax similar to an if/else
statement, except that the parenthesized expression goes after
the second keyword rather than the first. As with if/else,
there are two clauses, each of which may be a simple statement
ending with a semicolon or a brace-enclosed compound statement.
But whereas the else clause is optional, the Catch clause is
required. The expression must be a modifiable lvalue (something
capable of being assigned to) of the exact same type passed to
define_exception_type().
A Try/Catch statement has a syntax similar to an if/else statement,
except that the parenthesized expression goes after the second
keyword rather than the first. As with if/else, there are two
clauses, each of which may be a simple statement ending with a
semicolon or a brace-enclosed compound statement. But whereas
the else clause is optional, the Catch clause is required. The
expression must be an lvalue (something capable of being assigned
to) of the exact same type passed to define_exception_type().
If a Throw that uses the same exception context as the Try/Catch is
executed within the Try clause (typically within a function called
@@ -136,17 +135,9 @@ Catch (expression) statement
return, break, continue, goto, longjmp) is forbidden--the compiler
will not complain, but bad things will happen at run-time. Jumping
into or out of a Catch clause is okay, and so is jumping around
inside a Try clause. In many cases where one is tempted to return
from a Try clause, it will suffice to use Throw, and then return
from the Catch clause. Another option is to set a flag variable and
use goto to jump to the end of the Try clause, then check the flag
after the Try/Catch statement.
IMPORTANT: The values of any non-volatile automatic variables
changed within the Try clause are undefined after an exception is
caught. Therefore, variables modified inside the Try block whose
values are needed later outside the Try block must either use static
storage or be declared with the "volatile" type qualifier.
inside a Try clause. Also note that the values of any non-volatile
automatic variables changed within the Try clause are undefined
after an exception is caught.
Throw expression;
@@ -158,8 +149,8 @@ Throw expression;
be compatible with the type passed to define_exception_type(). The
exception must be caught, otherwise the program may crash.
Slight limitation: If the expression is a comma-expression it must
be enclosed in parentheses.
Slight limitation: The expression cannot be a comma-expression (but
no one would want to use a comma-expression here anyway).
Try statement