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Diffstat (limited to 'doc/langref.tex')
| -rw-r--r-- | doc/langref.tex | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/doc/langref.tex b/doc/langref.tex index 5b91d01d..973769d4 100644 --- a/doc/langref.tex +++ b/doc/langref.tex @@ -230,7 +230,7 @@ This prints: \end{verbatim} \end{vindent} Any larger number input to the function may exceed the MAXACTION or MAXNESTING -limits, which will be caught by the parser and result in an error. For more +limits, which will be caught at run time and result in an error. For more about limits see Section~\ref{sub:SystemTap-safety}. \newpage{} \subsection{The stap command} @@ -436,8 +436,10 @@ probe syscall.read = kernel.function("sys_read") { \index{epilogue-style aliases} \index{+=} The statement block that follows an alias definition is implicitly added -as an epilogue to any probe that refers to the alias. The following is an -example: +as an epilogue to any probe that refers to the alias. It is not useful +to define new variable there (since no subsequent code will see it), but +rather the code can take action based upon variables left set by the +prologue or by the user code. The following is an example: \begin{vindent} \begin{verbatim} @@ -445,15 +447,15 @@ example: # epilogue. # probe syscall.read += kernel.function("sys_read") { - fildes = $fd + if (traceme) println ("tracing me") } \end{verbatim} \end{vindent} \subsubsection{Probe alias usage} -Another probe definition may use a previously defined alias. The following -is an example. +A probe alias is used the same way as any built-in probe type, by +naming it: \begin{vindent} \begin{verbatim} @@ -1027,12 +1029,6 @@ type conversions between strings and numbers. Inconsistent type-related use of identifiers signals an error. -\subsubsection{Numbers} -\index{numbers} -Numbers are 64-bit signed integers. The parser will also accept (and wrap -around) values above positive $2^{63}$. - - \subsubsection{Literals} \index{literals} Literals are either strings or integers. Literals can be expressed as decimal, @@ -1041,10 +1037,10 @@ octal, or hexadecimal, using C notation. Type suffixes (e.g., \emph{L} or \subsubsection{Integers\label{sub:Integers}} -\index{integers} +\index{integers} \index{numbers} Integers are decimal, hexadecimal, or octal, and use the same notation as in C. Integers are 64-bit signed quantities, although the parser also accepts -(and wraps around) values above positive $2^{63}$. +(and wraps around) values above positive $2^{63}$ but below $2^{64}$. \subsubsection{Strings\label{sub:Strings}} |