diff options
Diffstat (limited to 'doc/SystemTap_Beginners_Guide/en-US/ScriptConstructs.xml')
| -rw-r--r-- | doc/SystemTap_Beginners_Guide/en-US/ScriptConstructs.xml | 63 |
1 files changed, 46 insertions, 17 deletions
diff --git a/doc/SystemTap_Beginners_Guide/en-US/ScriptConstructs.xml b/doc/SystemTap_Beginners_Guide/en-US/ScriptConstructs.xml index 42054cb9..b1f40669 100644 --- a/doc/SystemTap_Beginners_Guide/en-US/ScriptConstructs.xml +++ b/doc/SystemTap_Beginners_Guide/en-US/ScriptConstructs.xml @@ -47,9 +47,7 @@ probe timer.jiffies(100) { count_jiffies ++ } <para>In some cases, such as in <xref linkend="timerjiffies"/>, a variable may be declared without any specific value as yet. You need to declare such values as integers using the notation <command>++</command>.</para> </note> --> -</section> -<xi:include href="Arrays.xml" xmlns:xi="http://www.w3.org/2001/XInclude" /> - +</section> <section id="handlerconditionalstatements"> <title>Conditional Statements</title> <para> @@ -74,20 +72,21 @@ if (<replaceable>condition</replaceable>) <title>ifelse.stp</title> <programlisting> global countread, countnonread
-probe vfs.read,vfs.write
+probe kernel.function("vfs_read"),kernel.function("vfs_write")
{
if (probefunc()=="vfs_read") {
countread ++ }
else {countnonread ++}
}
-probe timer.s(5) {
- exit()}
-probe end {
- printf("VFS reads total %d\n VFS writes total %d\n", countread, countnonread)}
+probe timer.s(5) { exit() }
+probe end
+{
+ printf("VFS reads total %d\n VFS writes total %d\n", countread, countnonread)
+}
</programlisting> </example> -<para><xref linkend="simpleifelseexample"/> is a script that counts how many virtual file system reads (<command>vfs.read</command>) and writes (<command>vfs.write</command>) the system performs within a 5-second span. When run, the script increments the value of the variable <command>countread</command> by 1 if the name of the function it probed matches <command>vfs_read</command> (as noted by the condition <command>if (probefunc()=="vfs_read")</command>); otherwise, it increments <command>countnonread</command> (<command>else {countnonread ++}</command>).</para> +<para><xref linkend="simpleifelseexample"/> is a script that counts how many virtual file system reads (<command>vfs_read</command>) and writes (<command>vfs_write</command>) the system performs within a 5-second span. When run, the script increments the value of the variable <command>countread</command> by 1 if the name of the function it probed matches <command>vfs_read</command> (as noted by the condition <command>if (probefunc()=="vfs_read")</command>); otherwise, it increments <command>countnonread</command> (<command>else {countnonread ++}</command>).</para> </listitem> </varlistentry> @@ -103,11 +102,11 @@ while (<replaceable>condition</replaceable>) {<replaceable>statement</replaceabl <example id="simplewhileexample"> <title>while.stp</title> <programlisting> -global foo
-probe timer.s(1) {
-foo ++
-while (foo<6) {printf("hello world\n")}
-printf("goodbye world\n")
+global foo +probe timer.s(1) { +foo ++ +while (foo<6) {printf("hello world\n")} +printf("goodbye world\n") </programlisting> </example> @@ -137,10 +136,40 @@ for (<replaceable>argument1</replaceable>; <replaceable>argument2</replaceable>; --> </variablelist> - -<para>These constructs are better illustrated in the different examples available in <xref linkend="useful-systemtap-scripts"/>.</para> +<!-- +<para>These constructs are better illustrated in the different examples available in <xref linkend="useful-systemtap-scripts"/>.</para>--> + +<remark>need simple, simple examples for FOR and WHILE</remark> + +<formalpara> + <title>Conditional Operators</title> +<para>Aside from <command>==</command> ("is equal to"), you can also use the following operators in your conditional statements:</para> +</formalpara> + +<variablelist> + +<varlistentry> + <term>>=</term> + <listitem> + <para>Greater than or equal to</para> + </listitem> +</varlistentry> + +<varlistentry> + <term><=</term> + <listitem> + <para>Less than or equal to</para> + </listitem> +</varlistentry> + +<varlistentry> + <term>!=</term> + <listitem> + <para>Is not equal to</para> + </listitem> +</varlistentry> -<remark>will get back to these ones later</remark> +</variablelist> </section> <section id="commandlineargssect"> <title>Command-Line Arguments</title> |