c - Misra rule 19.7 : function like macro -

-

i have warning regarding misra rule 19.7 : function should used in preference function-like macro in below line : 

#define goffsetof(type, mem) (goffset)((size_t) ((char *)&((type *) 0)->mem - (char *)((type *) 0)))

how should solve ?

rule 19.7 (advisory): function should used in preference function-like macro. while macros can provide speed advantage on functions, functions provide safer , more robust mechanism. particularly true respect type checking of parameters, , problem of function-like macros potentially evaluating parameters multiple times.

the rule advisory, means "should followed":

note status of "advisory" not mean these items can ignored, should followed far reasonably practical. formal deviations not necessary advisory rules, may raised if considered appropriate.

so have option break rule without making formal deviation.

now, in answer question, "how should solve this?", have 2 choices given macro function can't implemented function.

option 1: deviate rule 19.7

the advisory makes clear functions nicer macro functions, , cites section in c traps , pitfalls, andrew koenig (1988) on comparing macro functions functions, describes preference, , on short macro functions designed "speed advantage".

if believe macro makes code clearer, conciser, , have suitably avoided common pitfalls of macro functions, can deviate rule 19.7 without making formal specific deviation, , without failing compliance.

option 2: remove macro function

if after considering advisory deem appropriate remove macro function. may want write more functions break inline code, and/or avoid needless code duplication.


Comments

Post a Comment

Popular posts from this blog

java - activate/deactivate sonar maven plugin by profile? -

-
i use sonar plugin executes if activated in maven profile. sonar runs on every compile. the problem build fail other team members not have sonar application installed locally. pom.xml checked in team members same copy including sonar configuration, don't want them modify purpose of disabling sonar (they might inadvertently check modified copy in). please advise how configure maven (.m2/settings.xml) and/or pom.xml sonar feature can enabled/disabled local profile. here sonar configuration in each project's pom.xml: <plugin> <groupid>org.codehaus.mojo</groupid> <artifactid>sonar-maven-plugin</artifactid> <version>1.0</version> <executions> <execution> <id>make-sonar</id> <phase>compile</phase> <goals> <goal>sonar</goal> </goals> </execution> </executions> ...
Read more

python - TypeError: can only concatenate tuple (not "float") to tuple -

-
i'm new python, question might easy, anyway, patience: as trying call newton-raphson method calculate implied volatility in black-scholes formula call/put option pricing, first thing is, newton method in scipy.optimize seems calculate function's zeros, in black-scholes formula, want function's value option price, not zero. (i'm new here programming, i'm not sure techniques.) should write function things like: def f(sigma, price): return bsformula(s0,k,r,t,q,sigma) - price then, while calling newton method, takes args=() 1 parameter in function, write this: value = newton(bsprice2, 0.5, args=price) but error message: file "bs.py", line 36, in bsimpvol value = newton(bsprice2, 0.5, args=float(price)) file "/usr/lib/python2.7/dist-packages/scipy/optimize/zeros.py", line 143, in newton q0 = func(*((p0,) + args)) typeerror: can concatenate tuple (not "float") tuple could tell me why that? how fix it? apprecia...
Read more

java - What is the difference between String. and String.this. ? -

-
this question has answer here: meaning of .this , .class in java 2 answers i'll straight point. im still learning bit of syntax , want know difference between code is code a: public class buttonz extends jbutton{ public buttonz(){ settext(new string(string.valueof(i))); } } please ignore fact i undeclared, not lost. code b: public class buttonz extends jbutton{ public buttonz(){ settext(new string(string.this.charat(i))); } } what don't yet understand difference in typing string.this , string. i under assumption when use dot operator on class accessing it's static methods(and/or variables if they're not hidden). i have studied little bit , have concluded when using string. accessing string static methods.. when using string.this. i'm accessing methods class buttonz extendi...
Read more