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stapex(3stap) [centos man page]

STAPEX(3stap)															     STAPEX(3stap)

NAME
stapex - systemtap examples LANGUAGE BASICS
These examples give a feel for basic systemtap syntax and control structures. global odds, evens probe begin { # "no" and "ne" are local integers for (i=0; i<10; i++) { if (i % 2) odds [no++] = i else evens [ne++] = i } delete odds[2] delete evens[3] exit () } probe end { foreach (x+ in odds) { printf ("odds[%d] = %d0, x, odds[x]) } foreach (x in evens-) { printf ("evens[%d] = %d0, x, evens[x]) } } This prints: odds[1] = 1 odds[3] = 5 odds[4] = 7 odds[5] = 9 evens[5] = 8 evens[4] = 6 evens[2] = 2 evens[1] = 0 Note that all variables types are inferred, and that all locals and globals are automatically initialized. This script prints the primes between 0 and 49. function isprime (x) { if (x < 2) return 0 for (i=2; i<x; i++) { if (x % i == 0) return 0 if (i * i > x) break } return 1 } probe begin { for (i=0; i<50; i++) if (isprime (i)) printf("%d0, i) exit() } This script demonstrates recursive functions. function fibonacci(i) { if (i < 1) error ("bad number") if (i == 1) return 1 if (i == 2) return 2 return fibonacci (i-1) + fibonacci (i-2) } probe begin { printf ("11th fibonacci number: %d0, fibonacci(11)) exit () } Any larger number may exceed the MAXACTION or MAXNESTING limits, and result in an error. PROBING
To trace entry and exit from a function, use a pair of probes: probe kernel.function("sys_mkdir") { println ("enter") } probe kernel.function("sys_mkdir").return { println ("exit") } To list the probeable functions in the kernel, use the listings mode. % stap -l 'kernel.function("*")' To list the probeable functions and local variables in the kernel, use another listings mode. % stap -L 'kernel.function("*")' MORE EXAMPLES
The directory to find more examples can be found in the stappaths(7) manual page, and online at http://sourceware.org/systemtap/examples/ SEE ALSO
stap(1) stapprobes(3stap) stappaths(7) STAPEX(3stap)

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STAPEX(3stap)                                                                                                                        STAPEX(3stap)

NAME
stapex - systemtap examples LANGUAGE BASICS
These examples give a feel for basic systemtap syntax and control structures. global odds, evens probe begin { # "no" and "ne" are local integers for (i=0; i<10; i++) { if (i % 2) odds [no++] = i else evens [ne++] = i } delete odds[2] delete evens[3] exit () } probe end { foreach (x+ in odds) { printf ("odds[%d] = %d0, x, odds[x]) } foreach (x in evens-) { printf ("evens[%d] = %d0, x, evens[x]) } } This prints: odds[1] = 1 odds[3] = 5 odds[4] = 7 odds[5] = 9 evens[5] = 8 evens[4] = 6 evens[2] = 2 evens[1] = 0 Note that all variables types are inferred, and that all locals and globals are automatically initialized. This script prints the primes between 0 and 49. function isprime (x) { if (x < 2) return 0 for (i=2; i<x; i++) { if (x % i == 0) return 0 if (i * i > x) break } return 1 } probe begin { for (i=0; i<50; i++) if (isprime (i)) printf("%d0, i) exit() } This script demonstrates recursive functions. function fibonacci(i) { if (i < 1) error ("bad number") if (i == 1) return 1 if (i == 2) return 2 return fibonacci (i-1) + fibonacci (i-2) } probe begin { printf ("11th fibonacci number: %d0, fibonacci(11)) exit () } Any larger number may exceed the MAXACTION or MAXNESTING limits, and result in an error. PROBING
To trace entry and exit from a function, use a pair of probes: probe kernel.function("sys_mkdir") { println ("enter") } probe kernel.function("sys_mkdir").return { println ("exit") } To list the probeable functions in the kernel, use the listings mode. % stap -l 'kernel.function("*")' To list the probeable functions and local variables in the kernel, use another listings mode. % stap -L 'kernel.function("*")' MORE EXAMPLES
The directory to find more examples can be found in the stappaths(7) manual page. SEE ALSO
stap(1) stapprobes(3stap) stapfuncs(3stap) stappaths(7) STAPEX(3stap)
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