c - Initializing a static variable in a function to a non-constant value -


I have a function that requires some continuous data, but call the function to get continuous data It is necessary that a linear search receives the statistics. I do not want to search for every call of the function, so I tried to make the static variable in question but the static variable can not be started for non-static values: < Pre class = "lang-c prettyprint-override"> int my_function (int foo) {static contact thing * bar = thing_from_name ("bar"); Return do_thing (foo, bar); }

The GCC complains correctly that "the initial element is not stable".

After considering my situation for a moment, I eat my cake and eat it too: 

 > int my_function Int foo) {static constant thing = bar = null; If (! Bar) bar = item_from_name ("bar"); Return do_thing (foo, bar); }   
 It still works fine, but it seems that ... is wrong. Is there any disadvantage for this approach? Is there a better way to solve my problem?  
 To be clear,  thing_from_name  is effectively a pure function, it only reads from continuous data in memory as it searches for the string, so for me one There is not really an easy way to customize continuous expression (as far as I know).  
 Edit: Here is a thick outline of  thing_from_name  for further reference:  
  const thing * thing_from_name (const char * name) {const thing * t; (T = & amp; Object_Ray [0]; T-> Name! = Faucet; T ++) {If (SRCMP (T-> Name, Name) == 0) {Return T; }} Return tap; }   
 
 
 For plain C, you probably have to use something similar if the  Thing_from_name ()  is fully expressed as a static code, which can be pre-computed on time compilation, you can succeed. If not, you should use your solution, but remember that this thread is not secure-safe.

Comments

Post a Comment

Popular posts from this blog

Verilog Error: output or inout port "Q" must be connected to a structural net expression -

I get the error every time, I try to compile. I'm not sure why anyone can help is? I'm new to verilog. Module D_FF (clerk, d, reset_n, q); Input D, Clack, reset_en; Output Q; reg Q; lab4_gdl f1 (.lk (~ clk), d (d), .q.m (qm)); lab4_GDL f2 (.Clk (Clk), D (QM), .Q (Q)); Always start at @ (posedge clk, neggeous reset_n) (Reset_n == 0) Q & lt; = 0; Other questions & lt; = D; Edit End: The problem is what we are asking to do: In this section, you apply the memory / registration circuit on the AlterEdie 2 board. will do. The circuit has the following specifications: The present value of swift SW15-0 on the D2 board should be shown in four hexadecimal four sections of HEX3-0. This part of the circuit will be combination logic. To use an active-less asynchronous reset and KEY1 to use KEY0 as the clock input, you must store SW15-0in in a 16-bit register in the value The register should be enabled to have a 16-bit positive edge, which uses the embedded D flip-flo
Read more

jasper reports - How to center align barcode using jasperreports and barcode4j -

I use iReport 5.5.0 . How to align a barcode component to the center The relevant piece of my jrxml is below & Lt; JR: Code 128 xmlns: JR = "http://jasperreports.sourceforge.net/jasperreports/components" xsi: schemaLocation = "http://jasperreports.sourceforge.net/jasperreports/components http: //jasperreports.sourceforge Purge / xsd / components.xsd "textPosition =" bottom "& gt; & Lt; Jr: codeExpression & gt; & Lt; [CDATA [$ F {number}]] & gt; & Lt; / Jr: codeExpression & gt; & Lt; / Jr: Code 128 & gt; & Lt; / componentElement & gt; "Text" itemprop = "text"> Create a style after this, it is called "barcode", like: & lt; Style name = "barcode" fontName = "Helvetica" fONTSIZE = "10" hAlign = "center" valign = "center" /> and set the property of your barcode element to "barcode".
Read more

c# - ASP.NET MVC - Attaching an entity of type 'MODELNAME' failed because another entity of the same type already has the same primary key value -

In brief, the wrapper module is inserted during posting and the status of an entry is changed to 'modified' . Before changing the state, the state is set to 'separate', but calling attachments () causes the same error to be thrown away. I am using EF 6. Model / wrapper class public class avi model {public A is a {get; Set; } Public listing & lt; B & gt; B {received; Set; } Public cc {receipt; Set; }} Administrator edit public functioning (int? id) {if (id == null) {new HttpStatusCodeResult (HttpStatusCode.BadRequest); } If (! Conveyor Access (id.Value)) new HTTPTitus code result (HTTP status code. Forbidden); Var aViewModel = new AViewModel (); aViewModel.A = db.As.Find (id); If (aViewModel.Receipt == zero) {return HttpNotFound (); } aViewModel.b = db.Bs.Where (x => x.aid == id.Value) .Oolist (); AViewModel.Vendor = db.Cs.Where (x => x.cid == aViewModel.a.cID) .FirstOrDefault (); See Return (aViewModel); } [HTPFost] [Valid AntitiferousTeacon
Read more