diff options
Diffstat (limited to 'stap.1.in')
| -rw-r--r-- | stap.1.in | 22 |
1 files changed, 18 insertions, 4 deletions
@@ -403,10 +403,16 @@ with optimized code. Some other events have very little context. New probe points may be defined using "aliases". Probe point aliases look similar to probe definitions, but instead of activating a probe at the given point, it just defines a new probe point name as an alias -to an existing one. This is identified by the "=" assignment -operator. In addition, the statement block that follows an alias +to an existing one. There are two types of alias, i.e. the prologue +style and the epilogue style which are identified by "=" and "+=" +respectively. + +For prologue style alias, the statement block that follows an alias definition is implicitly added as a prologue to any probe that refers -to the alias. For example: +to the alias. While for the epilogue style alias, the statement block +that follows an alias definition is implicitly added as an epilogue to +any probe that refers to the alias. For example: + .SAMPLE probe syscall.read = kernel.function("sys_read") { fildes = $fd @@ -420,7 +426,15 @@ which expands to .nh .IR kernel.function("sys_read") , .hy -with the given assignment as a prologue. Another probe definition +with the given statement as a prologue. And +.SAMPLE +probe syscall.read += kernel.function("sys_read") { + fildes = $fd +} +.ESAMPLE +defines a new probe point with the given statement as an epilogue. + +Another probe definition may use the alias like this: .SAMPLE probe syscall.read { |