diff options
Diffstat (limited to 'doc/bird.sgml')
| -rw-r--r-- | doc/bird.sgml | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/doc/bird.sgml b/doc/bird.sgml index 326fc7a8..f933128c 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -1260,8 +1260,8 @@ this: <code> filter not_too_far -int var; { + int var; if defined( rip_metric ) then var = rip_metric; else { @@ -1290,9 +1290,9 @@ local variables. Recursion is not allowed. Function definitions look like this: <code> function name () -int local_variable; { - local_variable = 5; + int local_variable; + int another_variable = 5; } function with_parameters (int parameter) @@ -1301,16 +1301,19 @@ function with_parameters (int parameter) } </code> -<p>Unlike in C, variables are declared after the <cf/function/ line, but before -the first <cf/{/. You can't declare variables in nested blocks. Functions are -called like in C: <cf>name(); with_parameters(5);</cf>. Function may return -values using the <cf>return <m/[expr]/</cf> command. Returning a value exits -from current function (this is similar to C). +<p>Like in C programming language, variables are declared inside function body, +either at the beginning, or mixed with other statements. Declarations may +contain initialization. You can also declare variables in nested blocks, such +variables have scope restricted to such block. There is a deprecated syntax to +declare variables after the <cf/function/ line, but before the first <cf/{/. +Functions are called like in C: <cf>name(); with_parameters(5);</cf>. Function +may return values using the <cf>return <m/[expr]/</cf> command. Returning a +value exits from current function (this is similar to C). -<p>Filters are defined in a way similar to functions except they can't have +<p>Filters are defined in a way similar to functions except they cannot have explicit parameters. They get a route table entry as an implicit parameter, it is also passed automatically to any functions called. The filter must terminate -with either <cf/accept/ or <cf/reject/ statement. If there's a runtime error in +with either <cf/accept/ or <cf/reject/ statement. If there is a runtime error in filter, the route is rejected. <p>A nice trick to debug filters is to use <cf>show route filter <m/name/</cf> |