segmentation fault - What is the simplest standard conform way to produce a Segfault in C? -

-

i think question says all. example covering standards c89 c11 helpful. though of one, guess undefined behaviour:

#include <stdio.h>  int main( int argc, char* argv[] ) {   const char *s = null;   printf( "%c\n", s[0] );   return 0; }

edit:

as votes requested clarification: wanted have program usual programming error (the simplest think of segfault), guaranteed (by standard) abort. bit different minimal segfault question, don't care insurance.

a segmentation fault implementation defined behavior. standard not define how implementation should deal undefined behavior , in fact implementation optimize out undefined behavior , still compliant. clear, implementation defined behavior behavior not specified standard implementation should document. undefined behavior code non-portable or erroneous , behavior unpredictable , therefore can not relied on.

if @ c99 draft standard §3.4.3 undefined behavior comes under terms, definitions , symbols section in paragraph 1 says (emphasis mine going forward):

behavior, upon use of nonportable or erroneous program construct or of erroneous data, this international standard imposes no requirements

and in paragraph 2 says:

note possible undefined behavior ranges ignoring situation unpredictable results, behaving during translation or program execution in documented manner characteristic of environment (with or without issuance of diagnostic message), terminating translation or execution (with issuance of diagnostic message).

if, on other hand, want method defined in standard cause segmentation fault on unix-like systems raise(sigsegv) should accomplish goal. although, strictly speaking, sigsegv defined follows:

sigsegv invalid access storage

and §7.14 signal handling <signal.h> says:

an implementation need not generate of these signals, except result of explicit calls raise function. additional signals , pointers undeclarable functions, macro definitions beginning, respectively, letters sig , uppercase letter or sig_ , uppercase letter,219) may specified implementation. the complete set of signals, semantics, , default handling implementation-defined; signal numbers shall positive.


Comments

Post a Comment

Popular posts from this blog

c# - How Configure Devart dotConnect for SQLite Code First? -

-
can configure following sample code ? when run following code, error : no entity framework provider found ado.net provider invariant name 'devart.data.sqlite' setting in machine.config <system.data> <dbproviderfactories> <add name="dotconnect sqlite" invariant="devart.data.sqlite" description="devart dotconnect sqlite" type="devart.data.sqlite.sqliteproviderfactory, devart.data.sqlite, version=4.6.287.0, culture=neutral, publickeytoken=09af7300eec23701" /> </dbproviderfactories> </system.data> after add below block code in app.config <?xml version="1.0"?> <configuration>   <configsections> <!-- more information on entity framework configuration, visit http://go.microsoft.com/fwlink/?linkid=237468 --> <section name="entityframework" type="system.data.entity.internal.configfile.entityframeworksection, entit...
Read more

java - Copying object fields -

-
what best way of copying classes when need have 2 independent variables? have simple class: public class myclass { boolean = false; string b= "not empty"; } do need make method : assign(myclass data ) { a= data.a; b= data.b; } is there automatic method copy (duplicate) objects in java? do need make method : pretty close. instead of making method, should make constructor. such constructors called copy constructor , , create them this: myclass(myclass data) { = data.a; b = data.b; } and create copy of instance, use constructor this: myclass obj1 = new myclass(); myclass obj2 = new myclass(obj1); copy constructor can tedious : using copy constructor create deep-copy can tedious, when class has mutable fields. in case, assignment create copy of reference, , not object itself. have create copy of fields (if want deep copy). can go recursive. a better way create deep copy serialize , deserialize object. why not use clone()? ...
Read more

c++ - Clear the memory after returning a vector in a function -

-
i have function processes , stores lot of data in , returns results vector of class. amount of data stored in function tremendous , want clear storage memory of function after finished job. necessary (does function automatically clear memory) or should clear memory function? update: vector<customers> process(char* const *filename, vector<int> id) { vector<customers> list_of_customers; (perform actions) return list_of_customers; } variables defined locally within function automatically released @ end of function scope. destructors objects called, should free memory allocated objects (if objects coded correctly). example of such object std::vector . anything you've allocated new must have corresponding delete release storage. try avoid doing own allocation , use raii instead, i.e. containers or smart pointers.
Read more